Contract Door Security Bolt, sometimes called a Rack Bolt. The bolt is morticed inside the door edge and can be locked or unlocked via a separate splined key or with a fixed splined turn. The bolt has an internal sawtooth rack mechanism into which the splined key is inserted. The spline engages with the rack teeth and forms a gearing action which smoothly operates the bolt. Splined Key or Turn to be ordered separately. Short and Long options available Comes with a 5 year mechanical guarantee and is fire rated FD30/60. Suitable for use in all domestic, industrial and commercial environments.