The Vario is a base unit that accepts one of six zip-on packs, ranging from 5-40 liters. The base holds a cartridge of nitrogen horizontally against the upper back with airbags on either side, keeping the weight symmetrical and the system away from the cargo area. The 25-liter zip- on is ideal for a day in the backcountry with a small pocket on top, two large compartments, and a helmet strap system. Both compartments are roomy, with a hydration sleeve in the front and tool organization in the rear. The whole system is just shy of seven pounds and the trigger handle points slightly inward from the left shoulder strap for easy activation.