it's a copy of the Futur handle, which I've owned and liked.
I don't like long handles (e.g. the 100mm standard Mongoose one that I tried on Erik's pass-around) and I found the Mongoose far too head heavy with a dia 12mm Bulldog 85mm , so much so that I was going to sell it. But before I sold it I wanted to try it with a handle that was max 85mm in length, more balanced like the Futur but less slippery than a polished Futur handle. One of the machinists at work made this for me (see above) but as his primary job is machining prototype engines finishing isn't his forte so last weekend I clamped it into a drill chuck and spent an hour with a great deal of wet and dry and Peek polish. It's not Mongoose perfect and the knurling leaves a lot to be desired but much nicer than it was.