Check the listing for details. SKB 3i-M3U13-FRM 3U Deep Rack Frame - 13 inches. Condition: New with tags. Listed at 169.99 USD. Lightweight Rack Frame for Mobile Creators Encased in a lightweight, injection-molded enclosure à la this Deep Rack Frame from SKB, your gear will remain protected, easily accessible, and mobile in the face of any onstage or in-studio performance. Threaded steel front and rear rails come with included screws for immediate installation, with up to 3U of rack space for single or double mounting options. Sweetwater's sound technicians have also noted that the frame's built-in rubber feet make for a seamless modular setup experience. Each rack frame is immediately compatible with it's corresponding Fly Rack case (not included) for even easier transport and better protection on the road. The bottom line? Your mobile rack assemblage is in no safer hands than SKB's Fly Rack system.