Large capacity seat bag specially designed for bikepackers providing a streamlined way to carry gear without the need for a rear rack Constructed of lightweight, durable, and water resistant material Upgraded saddle mount system reduces the pendulum effect of carrying large rear payloads, providing a comfortable, controllable ride for extended expeditions Integrated air release button keeps the inner waterproof bag compact Velcro Straps 23.6x7.9x7.1` 610 c.i. Black XX-Large (501-700 c.i.)