diff --git a/examples/examples/benchmark_bulk_xt.rs b/examples/examples/benchmark_bulk_xt.rs
index b60b327a9..96152ab34 100644
--- a/examples/examples/benchmark_bulk_xt.rs
+++ b/examples/examples/benchmark_bulk_xt.rs
@@ -28,7 +28,7 @@ use substrate_api_client::{
 	Api, SubmitExtrinsic,
 };
 
-// This example run against a specific  node.
+// This example run against a specific node.
 // We use the substrate kitchensink runtime: the config is a substrate config with the kitchensink runtime block type.
 // ! Careful: Most runtimes uses plain as tips, they need a polkadot config.
 // For better code readability, we define the config type.
diff --git a/examples/examples/compose_extrinsic_offline.rs b/examples/examples/compose_extrinsic_offline.rs
index b3be3963a..5c274d460 100644
--- a/examples/examples/compose_extrinsic_offline.rs
+++ b/examples/examples/compose_extrinsic_offline.rs
@@ -25,7 +25,7 @@ use substrate_api_client::{
 	Api, GetHeader, SubmitAndWatch, XtStatus,
 };
 
-// This example run against a specific  node.
+// This example run against a specific node.
 // We use the substrate kitchensink runtime: the config is a substrate config with the kitchensink runtime block type.
 // ! Careful: Most runtimes uses plain as tips, they need a polkadot config.
 // For better code readability, we define the config type.
diff --git a/examples/examples/contract_instantiate_with_code.rs b/examples/examples/contract_instantiate_with_code.rs
index f4761e96a..46e029b3f 100644
--- a/examples/examples/contract_instantiate_with_code.rs
+++ b/examples/examples/contract_instantiate_with_code.rs
@@ -25,7 +25,7 @@ use substrate_api_client::{
 	SubmitAndWatch, SubmitAndWatchUntilSuccess, XtStatus,
 };
 
-// This example run against a specific  node.
+// This example run against a specific node.
 // We use the substrate kitchensink runtime: the config is a substrate config with the kitchensink runtime block type.
 // ! Careful: Most runtimes uses plain as tips, they need a polkadot config.
 // For better code readability, we define the config type.
diff --git a/examples/examples/custom_nonce.rs b/examples/examples/custom_nonce.rs
index 2b744f20b..e4592b266 100644
--- a/examples/examples/custom_nonce.rs
+++ b/examples/examples/custom_nonce.rs
@@ -25,7 +25,7 @@ use substrate_api_client::{
 	Api, Error, GetHeader, SubmitAndWatch, UnexpectedTxStatus, XtStatus,
 };
 
-// This example run against a specific  node.
+// This example run against a specific node.
 // We use the substrate kitchensink runtime: the config is a substrate config with the kitchensink runtime block type.
 // ! Careful: Most runtimes uses plain as tips, they need a polkadot config.
 // For better code readability, we define the config type.
diff --git a/examples/examples/event_error_details.rs b/examples/examples/event_error_details.rs
index 252eb64df..9c7503c50 100644
--- a/examples/examples/event_error_details.rs
+++ b/examples/examples/event_error_details.rs
@@ -24,7 +24,7 @@ use substrate_api_client::{
 	Api, GetAccountInformation, SubmitAndWatchUntilSuccess,
 };
 
-// This example run against a specific  node.
+// This example run against a specific node.
 // We use the substrate kitchensink runtime: the config is a substrate config with the kitchensink runtime block type.
 // ! Careful: Most runtimes uses plain as tips, they need a polkadot config.
 // For better code readability, we define the config type.
diff --git a/examples/examples/get_account_identity.rs b/examples/examples/get_account_identity.rs
index 71b385ba0..f0407fa18 100644
--- a/examples/examples/get_account_identity.rs
+++ b/examples/examples/get_account_identity.rs
@@ -34,7 +34,7 @@ type BalanceOf<T> = <<T as pallet_identity::Config>::Currency as Currency<
 type MaxRegistrarsOf<T> = <T as pallet_identity::Config>::MaxRegistrars;
 type MaxAdditionalFieldsOf<T> = <T as pallet_identity::Config>::MaxAdditionalFields;
 
-// This example run against a specific  node.
+// This example run against a specific node.
 // We use the substrate kitchensink runtime: the config is a substrate config with the kitchensink runtime block type.
 // ! Careful: Most runtimes uses plain as tips, they need a polkadot config.
 // For better code readability, we define the config type.
diff --git a/examples/examples/get_blocks.rs b/examples/examples/get_blocks.rs
index 9ae21ad21..3e280e781 100644
--- a/examples/examples/get_blocks.rs
+++ b/examples/examples/get_blocks.rs
@@ -23,7 +23,7 @@ use substrate_api_client::{
 	Api, GetBlock, GetHeader, SubscribeChain,
 };
 
-// This example run against a specific  node.
+// This example run against a specific node.
 // We use the substrate kitchensink runtime: the config is a substrate config with the kitchensink runtime block type.
 // ! Careful: Most runtimes uses plain as tips, they need a polkadot config.
 // For better code readability, we define the config type.
diff --git a/examples/examples/get_storage.rs b/examples/examples/get_storage.rs
index 0c4f06b6f..e9c508898 100644
--- a/examples/examples/get_storage.rs
+++ b/examples/examples/get_storage.rs
@@ -24,7 +24,7 @@ use substrate_api_client::{
 	Api, GetAccountInformation, GetStorage,
 };
 
-// This example run against a specific  node.
+// This example run against a specific node.
 // We use the substrate kitchensink runtime: the config is a substrate config with the kitchensink runtime block type.
 // ! Careful: Most runtimes uses plain as tips, they need a polkadot config.
 // For better code readability, we define the different related types.
diff --git a/examples/examples/print_metadata.rs b/examples/examples/print_metadata.rs
index 941a9e378..ec599e653 100644
--- a/examples/examples/print_metadata.rs
+++ b/examples/examples/print_metadata.rs
@@ -19,12 +19,12 @@
 use sp_runtime::traits::GetRuntimeBlockType;
 use substrate_api_client::{ac_primitives::SubstrateConfig, rpc::JsonrpseeClient, Api};
 
-// This example run against a specific  node.
+// This example run against a specific node.
 // We use the substrate kitchensink runtime: the config is a substrate config with the kitchensink runtime block type.
 // ! Careful: Most runtimes uses plain as tips, they need a polkadot config.
 // For better code readability, we define the config type.
 type KitchensinkConfig =
-SubstrateConfig<<kitchensink_runtime::Runtime as GetRuntimeBlockType>::RuntimeBlock>;
+	SubstrateConfig<<kitchensink_runtime::Runtime as GetRuntimeBlockType>::RuntimeBlock>;
 
 #[tokio::main]
 async fn main() {
diff --git a/examples/examples/staking_batch_payout.rs b/examples/examples/staking_batch_payout.rs
index 8b66e310e..dc48e8744 100644
--- a/examples/examples/staking_batch_payout.rs
+++ b/examples/examples/staking_batch_payout.rs
@@ -24,7 +24,7 @@ use substrate_api_client::{
 
 const MAX_BATCHED_TRANSACTION: u32 = 9;
 
-// This example run against a specific  node.
+// This example run against a specific node.
 // We use the substrate kitchensink runtime: the config is a substrate config with the kitchensink runtime block type.
 // ! Careful: Most runtimes uses plain as tips, they need a polkadot config.
 // For better code readability, we define the config type.
diff --git a/examples/examples/sudo.rs b/examples/examples/sudo.rs
index 492ba9cfe..1c9226e8e 100644
--- a/examples/examples/sudo.rs
+++ b/examples/examples/sudo.rs
@@ -31,7 +31,7 @@ use substrate_api_client::{
 	Api, GetAccountInformation, SubmitAndWatch, XtStatus,
 };
 
-// This example run against a specific  node.
+// This example run against a specific node.
 // We use the substrate kitchensink runtime: the config is a substrate config with the kitchensink runtime block type.
 // ! Careful: Most runtimes uses plain as tips, they need a polkadot config.
 // For better code readability, we define the config type.
diff --git a/examples/examples/transfer_with_tungstenite_client.rs b/examples/examples/transfer_with_tungstenite_client.rs
index be2471e4b..4d8bfe0e8 100755
--- a/examples/examples/transfer_with_tungstenite_client.rs
+++ b/examples/examples/transfer_with_tungstenite_client.rs
@@ -27,7 +27,7 @@ use substrate_api_client::{
 	Api, GetAccountInformation, SubmitAndWatch, XtStatus,
 };
 
-// This example run against a specific  node.
+// This example run against a specific node.
 // We use the substrate kitchensink runtime: the config is a substrate config with the kitchensink runtime block type.
 // ! Careful: Most runtimes uses plain as tips, they need a polkadot config.
 // For better code readability, we define the config type.
diff --git a/examples/examples/transfer_with_ws_client.rs b/examples/examples/transfer_with_ws_client.rs
index 4f9d36d04..b73dcdfcd 100755
--- a/examples/examples/transfer_with_ws_client.rs
+++ b/examples/examples/transfer_with_ws_client.rs
@@ -27,7 +27,7 @@ use substrate_api_client::{
 	Api, GetAccountInformation, SubmitAndWatch, XtStatus,
 };
 
-// This example run against a specific  node.
+// This example run against a specific node.
 // We use the substrate kitchensink runtime: the config is a substrate config with the kitchensink runtime block type.
 // ! Careful: Most runtimes uses plain as tips, they need a polkadot config.
 // For better code readability, we define the config type.
diff --git a/primitives/src/config/substrate_config.rs b/primitives/src/config/substrate_config.rs
index 620b62f16..d00270436 100644
--- a/primitives/src/config/substrate_config.rs
+++ b/primitives/src/config/substrate_config.rs
@@ -21,8 +21,6 @@ use sp_core::sr25519;
 use sp_runtime::{traits::Block as BlockTrait, AccountId32, MultiAddress, MultiSignature};
 
 /// Default set of commonly used types by Substrate runtimes.
-// Note: We only use this at the type level, so it should be impossible to
-// create an instance of it.
 #[derive(Decode, Encode, Clone, Eq, PartialEq, Debug)]
 pub struct SubstrateConfig<Block> {
 	_marker: PhantomData<Block>,
@@ -36,7 +34,7 @@ where
 	type Hash = H256;
 	type AccountId = AccountId32;
 	type Address = MultiAddress<Self::AccountId, u32>;
-	type Signature = MultiSignature; //sr25519::Signature
+	type Signature = MultiSignature;
 	type Hasher = BlakeTwo256;
 	type Header = SubstrateHeader<u32, BlakeTwo256>;
 	type AccountData = AccountData<Self::Balance>;
diff --git a/primitives/src/extrinsics/signer.rs b/primitives/src/extrinsics/signer.rs
index f963ed825..9b2a20f7f 100644
--- a/primitives/src/extrinsics/signer.rs
+++ b/primitives/src/extrinsics/signer.rs
@@ -20,7 +20,8 @@
 use crate::config::Config;
 use codec::{Decode, Encode};
 use core::marker::PhantomData;
-use sp_core::Pair;
+use sp_core::{crypto::AccountId32, Pair};
+use sp_runtime::MultiAddress;
 
 pub trait SignExtrinsic<AccountId: Clone + Encode> {
 	type Signature: Encode;
@@ -84,7 +85,7 @@ where
 		&self.account_id
 	}
 
-	fn extrinsic_address(&self) -> T::Address {
+	fn extrinsic_address(&self) -> Self::ExtrinsicAddress {
 		self.extrinsic_address.clone()
 	}
 }
@@ -99,8 +100,7 @@ where
 		ExtrinsicSigner::<T, Signer>::new(value)
 	}
 }
-//Todo: check if still needed, because of config
-/*
+
 /// Extrinsic Signer implementation, that does not enforce Runtime as input.
 /// This is especially useful in no-std environments, where the runtime is not
 /// available.
@@ -149,7 +149,6 @@ where
 		self.extrinsic_address.clone()
 	}
 }
- */
 
 #[cfg(test)]
 mod tests {
@@ -172,7 +171,6 @@ mod tests {
 
 		assert_eq!(es_converted.signer.public(), es_new.signer.public());
 	}
-	// This test does not work. See issue #504.
 
 	#[test]
 	fn test_extrinsic_signer_clone() {
@@ -181,15 +179,4 @@ mod tests {
 
 		let _signer2 = signer.clone();
 	}
-
-	//Todo: still needed?
-	/*
-	   #[test]
-	   fn test_static_extrinsic_signer_clone() {
-		   let pair = AccountKeyring::Alice.pair();
-		   let signer = StaticExtrinsicSigner::<_, Signature>::new(pair);
-
-		   let _signer2 = signer.clone();
-	   }
-	*/
 }
diff --git a/src/api/rpc_api/chain.rs b/src/api/rpc_api/chain.rs
index f38b19a3a..f42f2a8ae 100644
--- a/src/api/rpc_api/chain.rs
+++ b/src/api/rpc_api/chain.rs
@@ -80,7 +80,7 @@ where
 	Client: Request,
 	<T::Header as ac_primitives::config::Header>::Number: Serialize,
 {
-	type BlockNumber = <T::Header as crate::config::Header>::Number;
+	type BlockNumber = <T::Header as ac_primitives::config::Header>::Number;
 	type Hash = T::Hash;
 	type Block = T::Block;
 
diff --git a/testing/examples/author_tests.rs b/testing/examples/author_tests.rs
index 84dc3ba36..bd845db8e 100644
--- a/testing/examples/author_tests.rs
+++ b/testing/examples/author_tests.rs
@@ -28,7 +28,7 @@ use substrate_api_client::{
 	Api, SubmitAndWatch, SubmitAndWatchUntilSuccess, SubmitExtrinsic, TransactionStatus, XtStatus,
 };
 
-// This example run against a specific  node.
+// This example run against a specific node.
 // We use the substrate kitchensink runtime: the config is a substrate config with the kitchensink runtime block type.
 // ! Careful: Most runtimes uses plain as tips, they need a polkadot config.
 // For better code readability, we define the config type.
diff --git a/testing/examples/chain_tests.rs b/testing/examples/chain_tests.rs
index 080cc4f52..5a07f3717 100644
--- a/testing/examples/chain_tests.rs
+++ b/testing/examples/chain_tests.rs
@@ -22,7 +22,7 @@ use substrate_api_client::{
 	Api, GetBlock, GetHeader, SubscribeChain,
 };
 
-// This example run against a specific  node.
+// This example run against a specific node.
 // We use the substrate kitchensink runtime: the config is a substrate config with the kitchensink runtime block type.
 // ! Careful: Most runtimes uses plain as tips, they need a polkadot config.
 // For better code readability, we define the config type.
diff --git a/testing/examples/events_tests.rs b/testing/examples/events_tests.rs
index 50b965eef..73446413b 100644
--- a/testing/examples/events_tests.rs
+++ b/testing/examples/events_tests.rs
@@ -39,7 +39,7 @@ impl StaticEvent for ExtrinsicSuccess {
 	const EVENT: &'static str = "ExtrinsicSuccess";
 }
 
-// This example run against a specific  node.
+// This example run against a specific node.
 // We use the substrate kitchensink runtime: the config is a substrate config with the kitchensink runtime block type.
 // ! Careful: Most runtimes uses plain as tips, they need a polkadot config.
 // For better code readability, we define the config type.
diff --git a/testing/examples/frame_system_tests.rs b/testing/examples/frame_system_tests.rs
index db181eb9c..3be0bd373 100644
--- a/testing/examples/frame_system_tests.rs
+++ b/testing/examples/frame_system_tests.rs
@@ -26,7 +26,7 @@ use substrate_api_client::{
 	Api, GetAccountInformation, SystemApi,
 };
 
-// This example run against a specific  node.
+// This example run against a specific node.
 // We use the substrate kitchensink runtime: the config is a substrate config with the kitchensink runtime block type.
 // ! Careful: Most runtimes uses plain as tips, they need a polkadot config.
 // For better code readability, we define the config type.
diff --git a/testing/examples/pallet_balances_tests.rs b/testing/examples/pallet_balances_tests.rs
index 53cbf0248..576532522 100644
--- a/testing/examples/pallet_balances_tests.rs
+++ b/testing/examples/pallet_balances_tests.rs
@@ -18,7 +18,7 @@
 use sp_runtime::traits::GetRuntimeBlockType;
 use substrate_api_client::{ac_primitives::SubstrateConfig, rpc::JsonrpseeClient, Api, GetBalance};
 
-// This example run against a specific  node.
+// This example run against a specific node.
 // We use the substrate kitchensink runtime: the config is a substrate config with the kitchensink runtime block type.
 // ! Careful: Most runtimes uses plain as tips, they need a polkadot config.
 // For better code readability, we define the config type.
diff --git a/testing/examples/pallet_transaction_payment_tests.rs b/testing/examples/pallet_transaction_payment_tests.rs
index 47c9807ea..163a1f7e2 100644
--- a/testing/examples/pallet_transaction_payment_tests.rs
+++ b/testing/examples/pallet_transaction_payment_tests.rs
@@ -25,7 +25,7 @@ use substrate_api_client::{
 	Api, GetBlock, GetTransactionPayment,
 };
 
-// This example run against a specific  node.
+// This example run against a specific node.
 // We use the substrate kitchensink runtime: the config is a substrate config with the kitchensink runtime block type.
 // ! Careful: Most runtimes uses plain as tips, they need a polkadot config.
 // For better code readability, we define the config type.
diff --git a/testing/examples/state_tests.rs b/testing/examples/state_tests.rs
index 7bcf631f5..c7d251aff 100644
--- a/testing/examples/state_tests.rs
+++ b/testing/examples/state_tests.rs
@@ -28,7 +28,7 @@ use substrate_api_client::{
 	Api, GetBlock, GetStorage,
 };
 
-// This example run against a specific  node.
+// This example run against a specific node.
 // We use the substrate kitchensink runtime: the config is a substrate config with the kitchensink runtime block type.
 // ! Careful: Most runtimes uses plain as tips, they need a polkadot config.
 // For better code readability, we define the related types.