I mainly climb pure ice routes with Vipers armed with BD Fangs. The Fang is the plastic piece that fits onto the bottom of the tool and makes it easier to hang onto. I've wanted an easier way to mach for a long time. I've wrapped a little shelf of tape, put a radiator clamp on there and tried some other tricks, but what I really wanted was a little bump to hang onto. Simple, wouldn't get wet, secure, etc. The photo to the left is of a prototype I've been working on with Black Diamond, you should see it in 2005. I've been using these on routes all season, they work great. Comfortable, far enough down the shaft and small enough that they don't get in the way, easy. These attach to any Viper out there in minutes. No, I don't have any spaire pairs, grin.
More photos here: