Commercial end bearing plates with a 4-3/8" shaft offset, sold as a left and right pair. These mount at each end of the torsion shaft and bolt to the wall with flanges for extra support on heavier doors. They hold the shaft level and keep the springs positioned correctly. If your current end plates are cracked or the bearing's shot, the shaft will start to drop on one side and the door won't balance right. These are commercial-grade for high-cycle and heavier door applications. Don't use residential end plates on a commercial door, they won't hold up.