Our Burra Burra Stabilizer Seatpack 20 is the largest in our line which means that you can say goodbye to the cumbersome weight & handling of integrated rear racks. Instead it affixes to your seatpost via an engineered aluminum stabilizer arm that minimizes any bouncing or side-to-side swaying under load. The pack itself features a welded roll closure design thats highly resistant to inclement weather while its larger size (55x 19x 10cm) makes it absolutely ideal for mid to larger sized frames.• Welded construction with a secure roll closure opening ensures reliable weather resistance & long-lasting durability.• Engineered aluminum stabilizer arm minimizes bouncing & shifting for more secure comfortable transport.• Urethane-coated YKK zipper pocket is designed to be highly weather resistant for dry storage of your smaller items.• Reflective accents increase your visibility to motorists in low-light conditions.• Stabilizer compatible with 27.2mm & 30.9mm seatposts.• Please note that this is not compatible with either dropper or carbon seatposts.• Dimensions (cm): 55 x 19 x 10• Weight: 450g