diff --git a/packages/yswaps/contracts/swappers/async/BancorSwapper.sol b/packages/yswaps/contracts/swappers/async/BancorSwapper.sol
index da61e36d..3c283214 100644
--- a/packages/yswaps/contracts/swappers/async/BancorSwapper.sol
+++ b/packages/yswaps/contracts/swappers/async/BancorSwapper.sol
@@ -32,13 +32,17 @@ interface IBancorNetwork {
   ) external payable returns (uint256 returnAmount);
 }
 
-interface IBancorSwapper is IAsyncSwapper {}
+interface IBancorSwapper is IAsyncSwapper {
+  function contractRegistry() external returns (IContractRegistry);
+
+  function bancorNetworkName() external returns (bytes32);
+}
 
 contract BancorSwapper is IBancorSwapper, AsyncSwapper {
   using SafeERC20 for IERC20;
 
-  IContractRegistry public contractRegistry;
-  bytes32 public bancorNetworkName;
+  IContractRegistry public immutable override contractRegistry;
+  bytes32 public immutable override bancorNetworkName;
 
   constructor(
     address _governor,
diff --git a/packages/yswaps/contracts/swappers/sync/BancorSwapper.sol b/packages/yswaps/contracts/swappers/sync/BancorSwapper.sol
index 7a4188ec..f325ea5b 100644
--- a/packages/yswaps/contracts/swappers/sync/BancorSwapper.sol
+++ b/packages/yswaps/contracts/swappers/sync/BancorSwapper.sol
@@ -30,13 +30,17 @@ interface IBancorNetwork {
   ) external payable returns (uint256 returnAmount);
 }
 
-interface IBancorSwapper is ISyncSwapper {}
+interface IBancorSwapper is ISyncSwapper {
+  function contractRegistry() external returns (IContractRegistry);
+
+  function bancorNetworkName() external returns (bytes32);
+}
 
 contract BancorSwapper is IBancorSwapper, SyncSwapper {
   using SafeERC20 for IERC20;
 
-  IContractRegistry public contractRegistry;
-  bytes32 public bancorNetworkName;
+  IContractRegistry public immutable override contractRegistry;
+  bytes32 public immutable override bancorNetworkName;
 
   constructor(
     address _governor,
diff --git a/packages/yswaps/contracts/swappers/sync/SyncSwapper.sol b/packages/yswaps/contracts/swappers/sync/SyncSwapper.sol
index c99601a6..a499abd8 100644
--- a/packages/yswaps/contracts/swappers/sync/SyncSwapper.sol
+++ b/packages/yswaps/contracts/swappers/sync/SyncSwapper.sol
@@ -31,7 +31,7 @@ abstract contract SyncSwapper is ISyncSwapper, Swapper {
     address _tokenIn,
     address _tokenOut,
     uint256 _amountIn,
-    uint256 _maxSlippage
+    uint256
   ) internal pure {
     if (_receiver == address(0) || _tokenIn == address(0) || _tokenOut == address(0)) revert CommonErrors.ZeroAddress();
     if (_amountIn == 0) revert CommonErrors.ZeroAmount();