diff --git a/nx01-no2all-nostr/src/main/java/love/distributedrebirth/no2all/nostr/model/NoStrSubscriptionFilter.java b/nx01-no2all-nostr/src/main/java/love/distributedrebirth/no2all/nostr/model/NoStrSubscriptionFilter.java
index 99353e4..d6c4ce9 100644
--- a/nx01-no2all-nostr/src/main/java/love/distributedrebirth/no2all/nostr/model/NoStrSubscriptionFilter.java
+++ b/nx01-no2all-nostr/src/main/java/love/distributedrebirth/no2all/nostr/model/NoStrSubscriptionFilter.java
@@ -17,7 +17,7 @@ import love.distributedrebirth.no2all.nostr.model.event.NoStrEventTagMeta;
 import love.distributedrebirth.no2all.nostr.nip.NoStrImplChuch;
 import love.distributedrebirth.no2all.nostr.nip.NoStrImplQName;
 
-public class NoStrSubscriptionFilter implements NoStrGospel {
+public final class NoStrSubscriptionFilter implements NoStrGospel {
 
 	private final static String TAG_FILTER_PREFIX = "#";
 	private final List<String> ids = new ArrayList<>();