It is a Castor Lockable in showcase system. It acts as a wheel, but it has brakes. The lockable castor is assembled into the screw hole of bottom corner for showcase or the bottom of the extrusions. After assembling castor, the showcase can be pushed freely and braked anytime. Select castors different castors who has different diameter screws according to different screw hole diameters of bottom corner for showcase. It weighs 0.080kg per each. Its screw’s diameter is 10mm. It is plastic. The products of LingTong are green and environmentally friendly. If there are some relative needs, LingTong will provide the best service for you in exhibition construction.