No restriction of movement and superior ventilation on all your biking trips: the rock surfer 18.5 is a compact day pack for biking trips in the great outdoors. We have equipped the pack with our flex motion suspension system, which was custom-developed for biking. It has well-padded shoulder straps and four contact points which are very flexible and adapt to your body. As a result, the pack provides a very good fit and great ventilation because air can flow freely between the contact points and your back. Our special, innovative Velcro fastener allows you to adjust the Elasticated waist belt as desired.The clever details also include Elasticated inserts around the zips, making them easy to operate even when the pack is full to bursting. We have also given the rock surfer an Elasticated helmet attachment and a fastener for your LED light.