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 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 / 19.8 lbs Carry Location: Rear Number of Compartments: 1 Dimensions: 16.5" Height x 9" Lower Width/12.6" Upper Width x 6.7" Depth Total Volume: 20 L / 1220.5 cu in Access Style: Roll Top Individual or Pair?: Individual Off Bike Carrying Method: Handle Waterproof: Yes Weight: 820g.