Fully adjustable rollers ensure smooth and safe sliding. sliding door track can be used with 3 inch thick doors, suitable for all brands of barn doors. Flush bottom design allows door needn't grooved and do not destroy your beautiful floor. Make your sliding door panel more smooth and keep your barn doors on the wall and do not swing either. This roller floor guide is easy to install, attach 2 screws to the bottom plate of the floor, adjust and tighten, that the roller will be fixed in the working position. Carbon steel frame with black surface, matching screw for maximum durability. The sliding door guides feature built-in bearings that provide ultra-smooth rolling and are easy to use. All wheels are equipped with 2 ball bearings, the bearings provide an ultra-smooth reel with effortless rolling with every glide. Note: The data are all measured manually, please allow 1-3cm error due to differences in light and display, there may be some color differences, please refer to the actual