diff --git a/src/header.rs b/src/header.rs
index 0eb4e8c..975428d 100644
--- a/src/header.rs
+++ b/src/header.rs
@@ -253,6 +253,7 @@ pub enum TypeFlag {
 
 bitflags::bitflags! {
     /// UNIX file permissions on octal format.
+    #[repr(transparent)]
     #[derive(Debug, Clone, Copy, PartialEq, Eq)]
     pub struct ModeFlags: u64 {
         /// Set UID on execution.