Rockwood 557 Lever Extension Flush Bolt Features: 3/4" bolt throw, 3/4" backset; door strength maintained by corner reinforcing plate, 557 Flush Bolt Is For Fire Rated Plastic and Wood Covered Doors measuring up to 4'w x 10'h rated up to and including 1-1/2 hours. Use Rockwood Part #570 Dust Proof Strike to prevent dirt blocking the bottom strike.
