Alpinestar's new Tech-Air vest is a modular system that riders can zip into compatible suits and jackets. There's a back protector that houses the electronics and two gas cartridges, and the airbag itself extends down the back, over the shoulders, across the chest, and down over the abdomen. Accelerometers monitor the rider's movement and can sense a crash as it's happening and activate the airbag in just 25 milliseconds. There are airbag systems on the market from Dainese and a few others, but this is a standalone, self-contained system. No tethers, wires, or GPS required.