The Topeak MTX BeamRack Rear Bike Rack is designed for MTB or heavy commuting use on bikes that do not have eyelets and rack mounts. Improved QR mechanism is more secure and easier to use. Compatible with all MTX Trunk Bags, 20 lbs. carrying capacity. Includes two rubber bungees and safety reflector.Clamp : QR fits ø25.4~ø31.8mm (shims Incl.)Material : Aluminum BeamBag Compatibility : MTX QuickTrackSystemMax. Weight Capacity  : 9 kgs / 20 lbsAdded Features : Rubber BungeeSafety ReflectorRedLite MountTail Light MountSize (L x W x H) : 54 x 12.7 x 8.1 cm21.3x 5x 3.2Weight  :680 g / 1.50 lbs(A-Type) - For XS and S size frames(E-Type) - For S and M size frames(V-Type) - For M and L size frames