diff --git a/util/src/lib.rs b/util/src/lib.rs
index 02a6f4677..e6de4f977 100644
--- a/util/src/lib.rs
+++ b/util/src/lib.rs
@@ -156,5 +156,6 @@ pub use log::*;
 pub use kvdb::*;
 pub use timer::*;
 
+/// 160-bit integer representing account address
 pub type Address = H160;