Finish: Polished Brass FinishForend: Polished Brass FinishBox Strike Assembly: Painted to match forendCase Finish: Silver powder coatCase Size: 67mm x 108mm 2.5inBackSet: 40mm This is the measurement from the edge of the door to the centre of the keyhole.Centres: 57mm This is the measurement from the centre of the follower, which operates the handles, to the centre of the keyhole. In the UK this is commonly 57mm.