I got this adapter so from Steve Reilly so that I can mount my GM8 to my AP 8" portable pier last April as I waited for my AP900GTO. My AP900 has arrived and I don't need this adapter any more. Please note that I am selling the adapter only between my GM8 and the portable pier. This adapter was made by Le Seur and weighs about 15lbs. Please email me if you are interested.