Ultimate Direction PB 2.0 Adventure Vest Designed and endorsed by Peter Bakwin and updated for 2014 The pack that do anything for hiking, running, climbing, etc Weight: 11L (671 sq. Inch) Total Volume and 15.5 oz (21 oz with bottles) Comes with two 20 oz Ultimate Direction water bottles SIZING: S/M: 23-36 inch chest, M/L: 31-40 inch chest