The Hydro Sleeve is the perfect solution for carrying water bladders inside your Stone Glacier pack. It is large enough for any 3-liter bladder system. The Hydro Sleeve mounts on the sewn in 3/4" black trislides on the inside back-panel of all Stone Glacier bags. The hydration hose can be run through the right or left side of the Hydration Port at the top of all Stone Glacier packs. Hydro Sleeves also work great for packing food, clothing, or other loose gear.