There are two models of the Hammar Inflator. This Manual, M1 and a Manual/Automatic version, A1. Both are compatible so that you can upgrade from a Manual to a Manual/ Automatic and vice versa in minutes if you wish. Some big benefits of the Hammar Manual/Automatic Life Jacket Inflator, A1 Unique hydrostatic valve that protects the water sensitive element. No activation in rain, spray, splash or humidity. Gas cylinder located inside the lifejacket bladder. Cylinder protected against corrosion. Reduces snagging hazard. No service requirement of the Inflator Cap for 5 years. The Manual/Automatic version works like this: When the Inflator is lowered more than about 10 cm in the water, the hydrostatic valve opens and lets the water meet the water sensitive element that in turn releases a stainless steel coil spring. The spring then drives a needle into the end of the gas cylinder, which is now punctured so that the gas instantly fills the lifejacket. Total buoyancy is often reached within 4 _ 5 seconds. The Manual Inflator is activated by pulling the red handle. The gas cylinder is then punctured with a needle and the lifejacket inflates within seconds. Service and maintenance: The Manual/Automatic inflator needs replacement after use or after the five years expiry date. The Manual Inflator needs replacement after use. No expiry date