In addition to measures against wild animals such as bears, this item is used to alert other runners and hikers to your presence during trail running and other activities. It comes with a carabiner, allowing for one-touch attachment to backpacks or belt loops. The sound is like "karan karan" (*^^*) [Product Information] Brand: mont-bell Product: Trekking Bell Round Product Number: 1134180 Weight: 36g Size: 26×50mm (Carabiner) Φ38mm (Bell) Materials: Carabiner: Aluminum alloy, Body: Steel