The Air Tool MTB pump is Speialized's most dependable and durable big-volume frame pump. It's intended to be carried on the bike for use in all off-road conditions. You'll find that it features a new inverted design, so it greatly increases air capacity, which reduces pump time by up to two minutes. - All new inverted, double chamber design increases the air handling capacity by 28% compared to our previous design, reducing pumping time by up to two minutes. - Twist locking head reduces size and can be easily converted to fit Presta or Schrader valves. - Machined outer barrel for extra grip while pumping.. - All-aluminum inner and outer chamber for durable performance. - Water bottle boss mount included. - Max pressure: 60 PSI (4.1bar) - Volume-per-stroke: 100cc