Summit bags are built for mountaineering and the design features vary through the range of fill weights. Summit Alpine 300, 400 and 500 are lightweight bags for Alpine climbing, with simple box wall construction, half zip with waist height belay facility and no shoulder or zip baffles. The Summit 700 is designed for colder ascents and adds more features including a full length zip with down filled zip and shoulder baffles. Finally the 900 and 1100 models are designed for cold expedition use wit