Made from Zinc AlloyThis Thumbturn and Release is used to operate a Bathroom LockThumbturn & Release is used with a Lever on Square Rose and a Bathroom Lock for rooms which require PrivacySuitable Bathroom Lock YKBL2N-PC&PN or YKBL3N-PC&PNBackplate Length: 53Backplate Width: 53Diameter: Aperture (Letter plates):