diff --git a/packages/effect-fc/src/types/SubscriptionSubRef.ts b/packages/effect-fc/src/types/SubscriptionSubRef.ts
index dfbdc1c..b66dc99 100644
--- a/packages/effect-fc/src/types/SubscriptionSubRef.ts
+++ b/packages/effect-fc/src/types/SubscriptionSubRef.ts
@@ -1,4 +1,4 @@
-import { Chunk, Effect, Effectable, Option, type Predicate, Readable, Ref, Stream, Subscribable, SubscriptionRef, SynchronizedRef, type Types, type Unify } from "effect"
+import { Chunk, Effect, Effectable, Option, Predicate, Readable, Ref, Stream, Subscribable, SubscriptionRef, SynchronizedRef, type Types, type Unify } from "effect"
 import * as PropertyPath from "./PropertyPath.js"
 
 
@@ -85,6 +85,8 @@ extends Effectable.Class<A> implements SubscriptionSubRef<A, B> {
 }
 
 
+export const isSubscriptionSubRef = (u: unknown): u is SubscriptionSubRef<unknown, SubscriptionRef.SubscriptionRef<unknown>> => Predicate.hasProperty(u, SubscriptionSubRefTypeId)
+
 export const makeFromGetSet = <A, B extends SubscriptionRef.SubscriptionRef<any>>(
     parent: B,
     options: {