This item is provided by Crutchfield.com and includes free phone technical support for the life of the product. Details on how to take advantage of this service will be included with your package. Should you have any issues locating information on how to contact Crutchfield Technical Support, please contact this website's Customer Service department. Add easy mobility to your Sanus CFR1615 or CFR1620 component rack with this set of casters. What's in the Box: 1. 4 Swivel casters for Sanus Component Series racks