This product works perfectly with your machine to align your D1 Laser-engraving machine with the grid on the whiteboard and keep your D1 Laser-frame from moving. Laser-foot guide accessories are compatible with D1 Laser-engraving Installation : installation is very simple, just put one foot on the opposite corner of the engraving machine, and then screw it onto the waste wood. These laser-guided legs are used to lock D1 in the same position. The product is equipped with 4 mounting feet and 8 screws. Screw size is 4 inch x 1/2 inch. High quality materials: The products are made of high quality materials, which improves the service life of the products. Material: Plastic colour: black Package Contents: 4 x mounting feet 8 x screws 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.