diff --git a/contracts/pools/erc20.sol b/contracts/pools/erc20.sol
index 75fc0a3..49900d1 100644
--- a/contracts/pools/erc20.sol
+++ b/contracts/pools/erc20.sol
@@ -118,7 +118,7 @@ contract PoolToken is ReentrancyGuard, ERC20Pausable, DSMath {
     * @param tknAmt token amount
     * @return mintAmt amount of wrap token minted
   */
-  function deposit(uint tknAmt) public payable whenNotPaused returns (uint mintAmt) {
+  function deposit(uint tknAmt) external payable whenNotPaused returns (uint mintAmt) {
     require(msg.value == 0, "non-eth-pool");
     uint _tokenBal = wdiv(totalSupply(), exchangeRate);
     uint _newTknBal = add(_tokenBal, tknAmt);
diff --git a/contracts/pools/eth.sol b/contracts/pools/eth.sol
index 329ff9c..71a3fdb 100644
--- a/contracts/pools/eth.sol
+++ b/contracts/pools/eth.sol
@@ -115,7 +115,7 @@ contract PoolETH is ReentrancyGuard, ERC20Pausable, DSMath {
     * @param tknAmt token amount
     * @return mintAmt amount of wrap token minted
   */
-  function deposit(uint tknAmt) public whenNotPaused payable returns (uint mintAmt) {
+  function deposit(uint tknAmt) external whenNotPaused payable returns (uint mintAmt) {
     require(tknAmt == msg.value, "unmatched-amount");
     uint _tokenBal = wdiv(totalSupply(), exchangeRate);
     uint _newTknBal = add(_tokenBal, tknAmt);