I have (1) Lowrance 522 color gps unit, and (1) Lowrance 520 color gps unit, both units are the heads only, the 522 has the internal gps, and the 520 needs the antenna, both units are in great working order, and both units look like new. I have another unit on the front of my boat, so I would like to trade both of these units for one Lowrance unit with at least an 8" screen, and a internal gps unit so I dont need an antenna. If anyone is interested in trading out, let me know what unit you have, and maybe we can help each other out. Thanks!