It's a brake pad, of all things. On the Tektro website, it goes by the cryptic moniker of 720.12. Not even important enough to get a cutesy marketing-department name.
So what makes this thing so cool? It mates the replaceable-cartridge feature of a fairly common road brake pad (basically, the shape that everyone's copied from Shimano) with the long threaded stem and ball-and-socket adjustment of a modern cantilever/V-brake pad and provides a nice, thick, long-lasting pad without compromising fork blade/tire clearance when the brake is opened. Basically, it's a cyclocross design that makes a lot of sense for other canti-/V-brake-equipped bikes.
I stumbled on a set when I tried some flavor of Tektro mini-V brakes on my old touring bike. The brakes were fine (still have 'em somewhere), but when the bike passed on to another owner, I never gave them another thought... until the pads on my commuter bike's V brakes wore out and I didn't have any replacements. Pilfered these Tektro things off the old mini-Vs and was immediately wowed by the improvement. The commuter uses a full run of cable housing from lever to caliper on the rear brake, so it tends to be a bit mushy. Pair that with a long, thin mountain-style brake pad (and the toe-in needed to keep it from squealing), and the resulting feel is like a brake made of marshmallows. With these smaller, stiffer cartridges, the feel was crisp without any loss of power, and the brake flat-out refused to squeal, even with what seemed like woefully insufficient toe-in.
Having grown tired of constantly toeing in the pads on the tandem to save my stoker from the humiliation of brake squeak, I recently swapped these pads from the commuter to the tandem (noticing a theme in my garage, whereby Peter is robbed to pay Paul?) and was again wowed. A little more challenging to set up on the tandem's wider rim due to the pads' thickness, but well worth it. Crisp, powerful and quiet again, even with the tandem's long cable runs.
Of course, having talked these things up, my Google-fu can't find a source to actually purchase them on the interwebs without buying a whole brake. Kool Stop makes a cyclocross pad which looks like a fancier "skeleton" version with funky triple-compound inserts -- and when it comes to brakes, you can't go wrong with Kool Stop. Still, I imagine that if the Tektros can be bought somewhere, they'll probably be cheaper, making them a real sleeper upgrade for a lot of otherwise crappy brakes.