I looked at that thing, and kept thinking, I had owned one many years ago, sure enough, I started digging into the unused tool bin, and there it was. it doesn't have the fancy forward handle, like the one pictured, but its the same tool. It is nothing but a bunch of hacksaw blades cleverly bent, and riveted, together, with a handle. I didn't find it very effective on hard maple, which is why its in the seldom if ever used tool bin. Maybe the forward handle would help put more pressure on the cutting surface.
Hungry Horse