The Distance Between The Two Caster Wheels Is Adjustable. Thanks to the collaboration of guide rollers, guide rails and various accessories, there are 8 possible variants of installation, to choose the perfect fit according to your needs. Ideal for most sizes or types of sliding doors and barn doors! Quick Installation: Assembly is easy and only takes a few minutes. Simply attach the two screws to the bottom track and pull the roller track into place. You don't need to drill holes in the door and floor. The sliding door guide kit also includes a detailed user manual. Anyone can install it easily and without hassle. Sturdy and Quiet: The sliding door track is made of premium steel which has a longer service life. The surface of the floor rail is coated with wear-resistant black and with adhesive strips to protect the door from scratches. The floor sliding door has almost no device when opening and closing the sliding door. Floating bottom design: Due to the flat screws, the running track cannot damage the door and the floor slides smooth and silent. Floor guide for sliding doors There are no sharp edges or sharp corners. Smooth bearings can easily slide and then slide the door without pressure. Note: The data is manual measurement, please allow 1-69cm error, due to differences in light and screen, there will be a certain color difference, the specific received in kind prevail.