1. rubber material 2. protect the vehicles from hiting the obstacle when the backward., 3.warning the driver Model, CW01Base size, 600 x 130 mmheight, 110mmweight, 4.5kg/pc functionthe rubber wheel locator, mainly installed on the berth to prevent the vehicles from hiting the obstacle when stop backward, will play the role to protect the vehicles, it will be good racket files of the berth.