I dunno. I've seen a few that look similar, and some with different manufacturer numbers on them. I think the difference in price is usually either markup or that some suppliers buy in larger bulk than others and can offer a cheaper price. BobRob has them for $20, and that's about what I'd expect to pay for one. They used to be $25 from him, so $20 is a nice price. If they were significantly cheaper (less than $15) then I'd wonder about the source and quality...