diff --git a/src/actors/util/channels/channel.ts b/src/actors/util/channels/channel.ts
index e6c023e..4f03ab7 100644
--- a/src/actors/util/channels/channel.ts
+++ b/src/actors/util/channels/channel.ts
@@ -135,6 +135,9 @@ export interface DuplexChannel<TSend, TReceive> extends Disposable {
   close: () => void | Promise<void>;
 }
 
+/**
+ * A function that upgrades a channel.
+ */
 export type ChannelUpgrader<TSend, TReceive = TSend> = (
   ch: DuplexChannel<TSend, TReceive>,
 ) => Promise<void>;
diff --git a/src/actors/util/watch.ts b/src/actors/util/watch.ts
index 057ba97..3ac0a30 100644
--- a/src/actors/util/watch.ts
+++ b/src/actors/util/watch.ts
@@ -1,3 +1,4 @@
+export type { ChannelUpgrader } from ".//channels/channel.ts";
 /**
  * Watches events and returns async iterators for the events.
  */