Revelate Designs Spinelock Seat Bag. Features: The Spinelock integrates user tested and approved features like a one-way air purge valve, rear light slots, loop and bungee deck, and an external plastic bottom with a new patented attachment system. Innovative Spinelock stability system completely eliminates side to side sway Waterproof construction Quick release bag from bike One way, low profile, air purge valve Top mounted external webbing and bungee for additional storage Protective external plastic bottom frame sheet Made in the USA with domestic and imported materials Third party online sales strictly prohibited by manufacturer Specs: Capacity:610 cu in (10L) Color:black