A traditional Brighton pattern sash window sprung fastener for narrow stile window frames. Locking version. A classic method of fastening & locking sliding sash windows. To lock, pull the sprung toggle arm down & screw the knob into the keep. To unlock, unscrew the knob & the arm will automatically flip up to the vertical position allowing ample clearance between the moving sash windows. Available in an extensive range of finishes. Operating key WFKEY/4MMCP sold separately. Comes with a 10 year mechanical guarantee.