The Norton 1601BF door closer is basically the same as the other 1600 series closers, but has tremendous size flexibility. It fits interior doors up to 3' 8" and exterior doors up to 3' 6". The "BF" (Barrier Free) feature meets the requirements of the Americans with Disabilities Act (ADA) for reduced opening resistance. Non-handed. Regular or parallel arm applications with included brackets. Adjustable spring power on closer. Two-tooth Rack-and-Pinion contact for smoother operation. Separate non-critical regulating valves for closing speeds, latch speed and back check. 6 ea/case.