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. With the Salamander Designs SA/XR40 extended rear panel, you can make room for your larger components. The panel's designed for use with 4-shelf Chameleon racks and Synergy cabinets, like the Model 402 . It gives you an additional 3-1/2 of depth. Ventilation slots help your components remain cool. Thumbnut screws make it easy to attach or remove the panel with a twist of your fingers. What's in the Box: 1. Extended rear-panel 2. 4 Thumb-nuts 3. 4 Flat-nuts 4. 4 Drop-in nuts 5. 4 Washers 6. 4 Studs 7. Magnet 8. Hex-key 9. Installation Instructions