Material: 2 Pcs Barn door floor guides is consists of a heavy carbon steel valve body ; POM rollers to ensure its durability, will not damage door surface. Ball bearing design make the door slide quietly & smoothly. Ideal for any type of sliding door Flat bottom design: Flush sliding door bottom guide can be completely flat on the floorwithout grooving ; drilling. The bottom groove protects the floor from being scratched by screws and will not damage your floor, making it more stable ; beautiful Adjustable Sliding Door Guide : Can be freely adjusted, and the distance between the 2 rollers can be adjusted to adapt to the door panel. The maximum thickness can be used for doors of 62mm. It can effectively prevent the sliding door from swinging. Easy to install: It is installed on the wall with screws, and no groove required for door. By adjusting the position of roller on the track to fit your door panel and tighten the screws at the bottom of the guide;