RAB,
I have two of them, both the older model and the newer model. Alpha Mirage makes two sizes, a smaller and larger scale. I have the larger scale and have made a "group buy" for a bunch of friends several years ago. Make sure you get the correct weight for calabrating the scale. Except to pay over $2,000 plus the weight. Well worth it and is accurate to about 1% on solid masses over about 20 Grams. Weigh in the Air, drop in water underneath, push a button and it tells a close gold purity. Several different settings for Au or Cu biased golds alloys. Using the scale & XRF sure makes it difficult to make a bad buy. I use mine several times everyday and would not sell them. I am at home and don't have the model numbers in front of me. The latest machine has an optional tape printer..
Dan