Commercial top bracket support,if you need residential type,you can also check in our website 

Product introduction:

Commercial top bracket support is made of galvanized steel./2.5MM steel for 11MM shaft Montain holes on 4-3/4'' centre (vertically) for 7/16'' diameter stem roller.

So it works for safety,very important for garage door system safety protection.
Garage door can be dangerous task. Garage door springs and cables are under
extreme tension and require appropriate safety precautions. Working with
garage doors and openers could result in personal injury or death. We recommend all installations,
repairs, adjustments, and removals on garage doors be made by a qualified
garage door technician. Any attempts to install, repair, replace, adjust garage
doors or openers are done at your risk.