Blackburn: A great alternative to panniers or a backpack. Ideal for overnight trips, but also works well for commuting or long day trips.• Extra large capacity seat pack• Removable and welded, waterproof dry bag• Adjusts easily to larger or smaller volume cargo• Mounts quickly on almost any bike• Also works with many standard dry bags and other stuff sacks• 70D nylon, 4mm ripstop seatpack with water resistant treatment and backing• 516 Grams