Aero shaped wedge pack with easy-to-use quick release mounting system. Large openings swallow up all the things you take with you. Gussets hold the rear flap in place when open. Hard wearing fabric.Features: Expanding design on M & L models for extra capacityBuilt-in pump holder on M & L modelsTail light strap included1000 Denier Teflon coated fabric3M Scotchlite reflective safety stripMedium: 60-80 Cubic inches