diff --git a/src/lib/key-set.ts b/src/lib/key-set.ts
index fef601b..bd36a3e 100644
--- a/src/lib/key-set.ts
+++ b/src/lib/key-set.ts
@@ -1,4 +1,4 @@
-import { KeySet } from './key-set/-base';
+import { Key, KeySet } from './key-set/-base';
 import { all, KeySetAll } from './key-set/all';
 import { allExceptSome, KeySetAllExceptSome } from './key-set/all-except-some';
 import { KeySetNone, none } from './key-set/none';
@@ -13,6 +13,7 @@ export {
   none,
   some,
   // types and classes
+  Key,
   KeySet,
   KeySetAll,
   KeySetAllExceptSome,