PINNACLE A1 BACK SYSTEM (A1) Single Adjust back system Built around two body contoured alloy bars, this back system can adjusted with just one hand while on the move and will fit almost any back length perfectly. A great option for participants going on to Award expeditions or for those with high usage and variable loads. (SA) Self Adjust back system Two alloy bars distribute load onto the stable hip area while the robust adjustment system can be tailored to the wearer while on the body. The Self Adjust makes it quick and easy to change the back length by pulling the two webbing straps to suit different paticipants. (QA) Quick Adjust Back System Coupling a contoured alloy frame for load distribution with a webbing ladder arrangement for back length adjustment. The Quick–Step system offers uncomplicated adjustment to change the back size between users. (S) Short Back Size Look out for the S after the pack size. This means the harness has been designed for smaller frames with a narrower harness and unique hip belt for better comfort and fit. How to measure back length Back length is measured from the top of the iliac crest (the top of the hip) to the C7 vertebrae (where the shoulders meet the neck). Our back systems, like most, are measured in centimetres with our short back system ideal for those measuring between 46 – 56cm long and our standard back from 50cm – 60cm. RUCKSACK TECHNOLOGY EXPLAINED: BACKSYSTEMS