diff --git a/packages/react-strict-dom/src/shared/useElementCallback.js b/packages/react-strict-dom/src/shared/useElementCallback.js
index 09f7f2d1..56d76314 100644
--- a/packages/react-strict-dom/src/shared/useElementCallback.js
+++ b/packages/react-strict-dom/src/shared/useElementCallback.js
@@ -23,7 +23,7 @@ type OptionalCleanup = (() => void) | void;
  * WARNING: The callback should be stable (e.g. using `useCallback`).
  */
 export function useElementCallback<T>(
-  callback: (T) => OptionalCleanup
+  callback: (v: T) => OptionalCleanup
 ): CallbackRef<T> {
   const cleanupRef = useRef<OptionalCleanup>(undefined);
   return useCallback(
diff --git a/packages/react-strict-dom/src/types/Utilities.js b/packages/react-strict-dom/src/types/Utilities.js
index 3b3df59a..1cb88171 100644
--- a/packages/react-strict-dom/src/types/Utilities.js
+++ b/packages/react-strict-dom/src/types/Utilities.js
@@ -9,4 +9,4 @@
 
 export type ReactRef<T> =
   | { writeonly current: T | null, ... }
-  | ((T | null) => unknown);
+  | ((v: T | null) => unknown);