The Evoc Seat Pack BOA Saddle Bag 2L is a quick to fix seat post pack which utilizes the revolutionary Boa® Fit System. This Evoc saddle bag has an adjustable capacity due to it's roll-top closure. Evoc Seat Pack BOA Saddle Bag 2L Features Adjustable capacity due to roll-top closure Dropper post compatible Soft TPE seatpost protection Flexible main compartment closure that adjust to bag size Boa® Fit System For Easy And Secure Fixation 100% Waterproof