The G.Stop has a tough aluminium housing. Internal components are manufactured from aluminium alloys, stainless steel, steel, bronze, and plastics. The G.Stop’s anchorage shackle must be attached to a suitable anchorage that meets the strength requirements (see section 4.1) and positioned so as to minimise the fall distance. The G.Stop must be used in conjunction with a Full Body Harness. The lifelines safety hook must be fitted to the attachment point of the full body harness. The lifeline is spring tensioned so that it extracts and retracts from the unit, ensuring that there is no slack rope. This enables the user to move freely while helping to keep the potential fall distance to a minimum. In the event of a fall, rope is pulled out of the unit at an accelerating rate. On reaching the activation speed of approximately 1.5m/s, the braking mechanism will engage. The energy of the fall is dissipated and the user brought to a halt. There must be adequate clearance below the user to safely stop a fall. See sections 6 to 6.2. Once a fall has been arrested, the user remains suspended until rescued to a safe platform or the ground. To release the fall arrest brake, the suspended person must first be raised slightly to remove the load from the unit. The rope should then pull out from or retract into the unit, protecting the user during the rescue procedure.