I came across it looking on Ebay for some parts. I've never seen it, but then again, I've been out of the loop for a while. I think its pretty stupid of a design, but thats just me...
Looks like a piece of junk to me. I guess if you wanted to use a cc 7700 motor on 2s in something it would offer enough added reduction to get it geared right. Maybe for a nitro 2wd truck? But you can get those electric, so no point IMO.