diff --git a/safe_eth/util/util.py b/safe_eth/util/util.py
index f4f9048cb..2d3640386 100644
--- a/safe_eth/util/util.py
+++ b/safe_eth/util/util.py
@@ -1,5 +1,7 @@
 from typing import Any, Iterable, Sequence
 
+from eth_typing import HexStr
+
 
 def chunks(elements: Sequence[Any], n: int) -> Iterable[Any]:
     """
@@ -11,11 +13,11 @@ def chunks(elements: Sequence[Any], n: int) -> Iterable[Any]:
         yield elements[i : i + n]
 
 
-def to_0x_hex_str(value: bytes) -> str:
+def to_0x_hex_str(value: bytes) -> HexStr:
     """
     Convert bytes to a 0x-prefixed hex string
 
     :param value: bytes value
     :return: 0x-prefixed hex string
     """
-    return "0x" + value.hex()
+    return HexStr("0x" + value.hex())