MidWest Universal Dog Crate Casters give your crate portability and ease of movement. These two inch casters are designed to roll easily over hardwood floors & can lock into place. Installation is easy and can be done anywhere underneath the dog crate where two wires intersect. These dog crate casters will work on any standard wire dog crate & work best for lengths of 36, 42, & 48 inches. For proper support, six casters are recommended for larger dog crates. We at MidWest Homes for Pets understand your pet is a part of your family & that's why we ensure our products are manufactured with the highest quality control standards creating a safe home for your pet. MidWest Homes for Pets stands behind the quality of our products with a 1 Year Manufacturer. If you have any questions about our products our customer service department would be glad to help you. MidWest customer service can be contacted at: 1-800-428-8560, available 9:00 AM - 4:00 PM, Monday - Friday.