diff --git a/src/exercise/04.md b/src/exercise/04.md
index ec436721..de5b0a3c 100644
--- a/src/exercise/04.md
+++ b/src/exercise/04.md
@@ -24,7 +24,7 @@ for common use cases.
 - [downshift](https://github.com/downshift-js/downshift) (uses prop getters)
 - [react-table](https://github.com/tannerlinsley/react-table) (uses prop
   getters)
-- [`@reach/tooltip`](https://reacttraining.com/reach-ui/tooltip) (uses prop
+- [`@reach/tooltip`](https://reach.tech/tooltip) (uses prop
   collections)
 
 ## Exercise