Compact closer body is designed to fit into headers as small as 1-3/4″ 4″. Closer body is non-handed. One closer for both single-acting or double-acting doors. Accommodates maximum door weight of 250 lb (interior) or 200 lb (exterior). A pressure relief valve protects closer from damage caused by forced closing. An integral cushion limits door swing to 90. An auxiliary stop must always be installed in conjunction with RTS88. A mechanical backcheck slows down the door prior to contact with the cushion. Closing speeds are controlled by two non-critical adjustment valves. Sweep area is from 90 to 20. Latch area is from 20 to 0. Thermostatic valves insure constant closing speeds under varying temperatures. The RTS88 offers a cast-iron body along with heavy-duty ball bearings at the spindle. Steel cam and roller assembly is coupled to dual steel pistons.