Topeak DynaPack DX Bicycle Seat Post Mount Bag with Fixer Divided Main Compartment, One Zip Pocket 890 g / 1.96 lbs (bag w/frame) 9.7 l / 590 ci Capacity 420 Denier Nylon & EVA Foam Clamp fits 25.4 up to 34.9mm Seatpost Extra Water Repellency and Resistance to Staining RedLite Clip