Architectural quality sash fastener (brighton pattern). A traditional Brighton pattern sash window sprung fastener. A classic method of fastening and locking sliding sash windows. To lock, pull the sprung toggle arm down and screw the knob into the keep. To unlock, unscrew the knob and the arm will automatically flip up to the vertical position allowing ample clearance between the moving sash windows. Comes with a 10 year mechanical guarantee. Suitable for domestic use.