The ortlieb back roller classic ql21 pannier pair the lightweight durable and waterproof panniers have been designed to conquer the most rugged and challenging bike tours back roller classic panniers feature the ortlieb ql21 mounting system for secure and simple attachment to almost any rack the back roller classic takes the name from the way that the bag closes they roll up with a single clip and strap holding them shut its basic but it works very well the roll prevents water from g