Venus Optics 60mm f/2.8 2:1 macro lens

Does anyone have an opinion on this lens for underwater macro use? It is available in Canon, Nikon, Sony, and Pentax mounts and costs $379. The maximum 2:1 magnification sounds interesting on paper.

http://photorumors.com/2015/01/05/venus-optics-announced-new-60mm-f2-8-ultra-macro-lens-the-worlds-first-21-magnification-lens-with-infinity-focus/

Manual focus only. Do you have a 3d printer to make focus gear?

2-1 macro @ 18cm (about 6") sounds interesting. It should allow some working distance compared to a Nikon 60mm. You'd have to measure the body and compare to other lenses to find a focus gear that will work.