This was Shure's next best cartridge after the V15 series. It was released in the late 70s or early 80s, I think, and had a hyper elliptical stylus profile. It came in two forms, as a standard cartridge, and alternatively ( the AH - attached headshell version) built into an SME fit shell. The latter also had a screw that could be loosened to slide the cartridge body fore or aft for fine tracking angle adjustment. I'd used both carts for a few years (and still have them as spares ) till I got hold of a V15. It's got a very refined sound, tracks excellently, has an attached brush, and needs a high compliant tone arm, as its VTF is between 1 and 1.25 gms.
If you're considering buying one, you need to know that it's been out of production for more than 20 years. You may get a NOS piece, which might work just fine, but you would need to get a new stylus, which also turn up as NOS items on eBay and some online suppliers. You could also get a new HE stylus from Jico, or one with their SAS profile.