Revelate Terrapin Seat Bag rearaxlesize 12x148mmboostthru axle HED Vanquish RC4 Performance Disc HED Vanquish RC4 Performance Disc Carbon Tubeless 700c Wheelset BMC Timemachine 01 TWO Time Trial Bike 2018 Indie Rail attachment system and active camming hardware Super stable without added hardware Radio frequency welded drybag with air purge valve Protective external plastic bottom frame sheet Aluminum hardware at high stress points Composite internal top frame sheet Hypalon slots on drybag for rear light attachment Foam stiffened side panels with fiberglass compression stays virtually eliminating side to side bag sway without the need for external hardware