5 Lever BS Sashlock 64mm. The Latchbolt has the ET reverse function to save undoing the case so it can be reversed in seconds. British Standard BS3621 Rated Sashlock used as a matter of course by the national house builders. This lock provides a high degree of security and carries a 25 year mechanical guarantee. It has been CE and Certifire tested. suitable for use in all domestic, industrial and commercial environments.