diff --git a/landing/button.react.js b/landing/button.react.js
index fd9c298d6..c793196ea 100644
--- a/landing/button.react.js
+++ b/landing/button.react.js
@@ -1,21 +1,21 @@
 // @flow
 
 import * as React from 'react';
 
 import css from './button.css';
 
 type Props = {
-  +onClick: (e: Event) => Promise<void>,
+  +onClick: (event: SyntheticEvent<HTMLButtonElement>) => mixed,
   +children?: React.Node,
 };
 
 function Button(props: Props): React.Node {
   const { onClick, children } = props;
   return (
     <button className={css.btn} onClick={onClick}>
       {children}
     </button>
   );
 }
 
 export default Button;