The Ortlieb Back-Roller Core is the solid base bag among the Back-Rollers and yet 100% waterproof. With its robust polyester fabric, it's not only suitable for extended bike tours but also ideal for daily urban commutes. With the Back-Roller Core, you're always ready to transport important items dry and securely - whether it's on your way to work, shopping, or other urban adventures. A reliable companion that withstands the elements and simplifies your everyday life. If the basic functions of the Back-Roller Core are ever insufficient, this practical bag can be expanded with various optional accessories. The Carrying System Bike Pannier helps carry the Back-Roller Core on your back, various inserts provide stability to the bag body off the bike, or offer better organization inside the rear bike bag. QL2.1 mounting system for racks up to 8, 10, 12 and 16 mm Waterproof gag made of PVC coated polyester fabric Top QL hooks and lower sliding hook adjustable without requiring any tools Lower hook rail synthetic to reduce abrasions on rack Highly reflective Scotchlite reflector Easy to clean inside Maximum load per pannier is 9kg / 20 lbs Specifications Total Volume20Carry LocationRearNumber of Compartments1Off Bike Carrying MethodHandleColorRed/ BlackWaterproofYesIncludes Rain CoverNoAccess StyleRoll TopWeight820Individual or Pair?IndividualDefined ColorRedDimensions17 x 23-32 x 42