The Medium Duty Surface Mount Overhead Door Holder & Stop is designed for interior, single acting, medium weight doors with moderate traffic. Door can be mounted with hinges, swing clear, offset pivots or center hung. Shock absorbing spring provides a 3 to 5 degree cushion before a dead-stop. Standard installation from 85 to 110 degrees of opening (5 degree increments). Standard fasteners supplied with sex bolts for 1-3/4" to 1-7/8" thick doors.