SRT Australia D1a and Kong Indy stop-style descenders. The SRT is single-stop (stops when you let go) and has approximately 5000' of use. It's still in great condition though with minimal visible wear (the sticker is still on it). The Kong is a double-stop (stops when you let go and when you squeeze too hard) and has only been used once. Here is a hi-res pic of both:
http://mohodisco.com/stops.jpg
Make me an offer if you're interested.