Cypres

CYPRES is an acronym for Cybernetic Parachute Release System. It refers to a specific make and model of an automatic activation device (AAD), a device that automatically activates a parachute (typically as a reserve system for a skydiver) under certain circumstances. A CYPRES is designed to activate the reserve parachute at a preset altitude if the rate of descent is over a certain threshold. The manufacturer of the CYPRES is Airtec.
The CYPRES works by using a cutter to cut the reserve container closing loop. A spring-loaded pilot chute then leaves the container and breaks through the skydiver's slipstream to begin reserve deployment.
The CYPRES comes in five different models: Expert, Student, Tandem, Speed and Wingsuit. The basic operation of the units is the same; only the activation parameters are different, having been optimized for different types of skydiving.