These retainers are mounted on the side of the bed frame and on the center support rail using two pins, which you can use pre drilled holes to secure to the bed frame Made of plastic, abrasion resistant black, suitable for all types of bed board If the size is right, no additional tools are required to install. Place the bedplate in the bracket and align the plastic pins with the mounting holes These plastic covers are perfect repair and replacement parts for metal beds, leather beds, wooden beds, sofa beds, bunk beds, etc Suitable for mounting spring plank with width between 57mm and thickness of 9mm color: Black material: plastic Package Contents: 40 x Bed Base Caps Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.