The RCBS 10-10 is the top of the line balance scale and I've had one for years. They're made for RCBS by Ohaus. I tend to use my 5-10 more often because it's just as accurate and I leave it set up. The 10-10 offers additional capacity with its auxiliary weight and is safer to transport because of the way everything locks down under the plastic cover. I also have an RCBS electronic scale, but prefer the balance type because they don’t need batteries or go bad.
Over the years, I managed to pick up a spare 10-10 that I recently put on ebay. It was like new and brought just over $100, so they're not cheap. New ones at Sinclair are over $150. Unless you travel with it or need to weigh things over 510gr, I suggest getting a clean used 5-10 instead.