The Heavy Duty Surface Mount Overhead Door Holder & Stop is designed for interior or exterior use. For use on single acting, heavy weight doors with frequent traffic. Door can be mounted with hinges, 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 2" thick doors.