[math-fun] Tokieda's big rattleback

In at least one online recording (that I can't locate) of T. Tokieda's toy talk (e.g., https://www.youtube.com/watch?v=f07KzjnL2eE), instead of his usual small plastic ones (with or without testudinal passengers) he had a large wooden (rosewood?) (outwardly) symmetrical one which he rubbed in his hair (ha ha) to reverse the preferential direction. Can someone suggest where to buy such a thing? Maybe not symmetrical. Maybe not wood. But fairly large? (I've heard of making them from old automobile bumpers. Maybe that's too large.) --rwg