The Lowe Alpine Universal Chest Strap is a great addition to any back pack. It ensures the shoulder straps are sitting in the optimum position. In fact it is noticeable how much more comfortable carrying a pack is, when using a chest strap. The Chest Strap will fit most pack shoulder straps, while the elasticated section allows for some movement. The buckle has an built in whistle, which is ideally positioned & useful in an emergency.