This Golden Grace Polished Chrome Nickel Plated Bolt Through Tubular Dead Bolt is 2.5 inches (64mm) and designed for bathroom locks. It features a 45mm backset, measuring from the edge of the door to the spindle hole. This deadbolt is ideal for use with bathroom thumbturns on rose and comes in a nickel-plated chrome finish from the Golden Grace Range. It is manufactured by Sumison Ltd.