Check the listing for details. Backpack Chest Strap [1PCS] - with Emergency Whistle Buckle - [Blue]. Condition: New. Listed at 14.29 USD. PRODUCT INTRODUCTION1. Features&ApplicationsOur non-slip backpack chest strap is made of polyester, resistant to wear and pull for long-term use. The quick-release design can be quickly and easily connected and released, and the two adjustable buckles can adjust the length according to the body type, effectively preventing the backpack from loosening and falling, evenly distributing weight. The buckle also includes a whistle that can be blown outdoors to signal to a companion or issue a warning.Our versatile backpack chest strap is suitable for various bags, including children's backpacks, adult outdoor sports bags, and travel backpacks. It prevents slippage, frees up your hands and secures loads, making it great for hiking, fishing, rock climbing, camping, cycling, and other outdoor activities.2.