Engineered using a CAD program?
The handle is just a piece of bar stock. The crank pulley insert is just a nut (look inside you can still see the threads) mounted on a piece of pipe mounted on a shaped plate. If the guy did actually go through the effort of drawing it up in cad rather than a paper napkin hes got too much time on his hands.

Still though apart from that $45 bucks isnt a bad price when the other tools on the market are going for $100+.