The Ortlieb Back Roller Free QL3.1 is designed to handle even the roughest conditions. The Back Roller Free is made from abrasion-resistant PVC free fabric, making a very durable and long-lasting bags. The Ortlieb Back Roller Free QL3.1 features a convenient roll-top closure system which makes for easy opening and closing as well as the ability to adjust the volume of the bag quickly and easily. Best of all it's completely waterproof and will protect your items from the elements. The Ortlieb Back Roller Free features the QL3.1 attachment system which makes installing the bag on your bike quick, easy, and secure! The Quick-Lock3.1 assembly set is equipped with three attachment points and can be attached to any standard luggage rack. The height and inclination can be adjusted individually. The locking elements on the back of the bag are flat and ideal for everyday use. Sold as a single bag.