Durable, kink-free sip tube and push-lock cushioned bite valve, gently biting the valve to open up the flow of water; Large 2 opening for ice cube and easy cleaning. Hydration Pack made rugged 800D Oxford fabric and nylon lining, resistant to tears and abrasion. Durable plastic insert buckles with ultra-high hardness. only 21 ounces with adjustable shoulder straps, The ergonomic design makes your back more comfortable.