diff --git a/nearby/framework/java/android/nearby/NearbyManager.java b/nearby/framework/java/android/nearby/NearbyManager.java
index 6e40524..4147c9a 100644
--- a/nearby/framework/java/android/nearby/NearbyManager.java
+++ b/nearby/framework/java/android/nearby/NearbyManager.java
@@ -105,6 +105,8 @@
         mService = service;
     }
 
+    // This can be null when NearbyDeviceParcelable field not set for Presence device
+    // or the scan type is not recognized.
     @Nullable
     private static NearbyDevice toClientNearbyDevice(
             NearbyDeviceParcelable nearbyDeviceParcelable,