diff --git a/Swipeable.js b/Swipeable.js
index <HASH>..<HASH> 100644
--- a/Swipeable.js
+++ b/Swipeable.js
@@ -25,7 +25,7 @@ export type PropType = {
   rightThreshold?: number,
   overshootLeft?: boolean,
   overshootRight?: boolean,
-  overshootFriction?: number,
+  overshootFriction: number,
   onSwipeableLeftOpen?: Function,
   onSwipeableRightOpen?: Function,
   onSwipeableOpen?: Function,
Swipeable flow type errors fix (#<I>)