The electronics should also be inspected before or after investing in the cost of replacing the garage door panel to make sure your door will operate properly. The sensors prevent the door from closing on someone's foot or a pet. If they don't work, someone could be injured. Also check to make sure the door opener works, since you could otherwise be locked out of your garage.
A typical version of an overhead garage door used in the past would have been built as a one-piece panel. The panel was mounted on each side with unequal parallelogram style hinge lifting mechanism. Newer versions of overhead garage doors are now generally built from several panels hinged together that roll along a system of tracks guided by rollers. The weight of the door may be 400 lb (181.4 kg) or more, but is balanced by either a torsion spring system or a pair of extension springs. A remote controlled motorized mechanism for opening garage doors adds convenience, safety, and security.