ERA Saracen Surelock Cego Door lock case gear box only, suits full length Saracen ERA or Surelock door locks and matches the later Cego lock with a 92mm spindle centre(not the 70mm). In some earlier versions of door locks the deadbolt used was slightly thinner by approximately 2mm or so. If this is the case then you may find that you need to file the slot on the faceplate and make it wider to allow for the new replacement gearbox