diff --git a/src/main/java/net/minestom/server/utils/time/Cooldown.java b/src/main/java/net/minestom/server/utils/time/Cooldown.java
index e96449c7b..6f3703b48 100644
--- a/src/main/java/net/minestom/server/utils/time/Cooldown.java
+++ b/src/main/java/net/minestom/server/utils/time/Cooldown.java
@@ -8,7 +8,7 @@ import java.time.temporal.TemporalUnit;
 @SuppressWarnings("removal")
 public final class Cooldown {
 
-    private Duration duration;
+    private final Duration duration;
     private long lastUpdate;
 
     /**