Adjustable shoulder/chest straps. Fit chest sizes from teenagers/kids with 27 inch up to adults (men and women) with 50 inch chest size. The chest straps make sure it doesn't bounce when you move; Whistle buckle compatible with emergency.The strap is also equipped with a hose clamp to easily fix the position of the hoseRugged Polyester heavy-duty construction with lining, BPA Free,resistant to tears and abrasion; Hands-free hydration hose with bite valve, gently biting the valve opens up the flow of waterLIGHTWEIGHT EASY TO CARRY: If you've been looking compatible with a lightweight, compact, and stable insulated hydration packs, then your search is over That's because our running water backpack has an athletic low-profile design that won't create a ton of wind resistance or bounce when your running, biking, hiking or at festivals. The Padded Mesh backing, and straps helps to keep you cool, comcompatible withtable and dryMaterial:Nylon+Polyestercolour:BlackPackage Contents:1 * backpack1 * water bottle bagOnly the above package content, other products are not included.Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.