The 4000T Series wall pocket heavy-duty closer is designed for use with an SEM 7850 wall magnet, to control the fire and smoke barrier doors with a maximum swing of 90 deg. UL and cUL listed for self-closing doors. Cast iron cylinder with full-complement bearing, 1-1/2"diameter piston, and double heat-treated steel pinion journal. The 4000T Series mounts wall pocket mount on hinge pull side with a standard track arm. Designed for interior doors 34-42" wide.