A very handy container for your pocket items or a water bladder.
At 135 cubic inches, the seat bag is large enough to hold your wallet, keys, bike tools, etc. It will even fit most standard size water bladders. The bag slips over the back or bottom of the seat and can easily be removed and carried by a handle on the top. It has a zipper closure under a protective flap. This bag is very durable, puncture resistant, flexible, and water repellant.