Kent, The one I have came with the cat when I bought it. I have no idea where it originally came from. I checked the web and was unable to locate one. My rack looks very similar if not not exactly like the photo above except it has a clamping type bracket for the front crossbar. Makes it easy to yank off if you don't want it on the boat. I originally thought the one in the pic above might have been a battery box because of its mounting position. Hobie sells one for batteries in the catalog that mounts under the front crossbar. It is obvious that a battery would not stay in the one above without a bottom and sides. DUH!!