As woodworkers, the first question on our lips is "how do you sharpen it"?
A very clever, simple design, but the sales pitch needed to cover the sharpening to maximize sales. The reason why the sharpening is not explained is because it gives the secret away about how the tool is made and also shows how grossly overpriced it is.
The sharpening tool, shown in the sales image, is basically a sanding block for emery cloth or wet-n-dry paper I suspect.
I agree with Bob; great for large jobs but not practical for small, fiddly jobs like crank bodies.
Dave