The Vario Clipper was the best chopper on the market, but the company quit making them. I am glad to have a couple of them.
But we are fortunate that Herb's Archery has essentially copied the Vario with some slight modifications that Herb says improve the original design. These choppers will last virtually forever and do a wonderful job of easily cutting feathers that are absolutely consistent. And you can quickly change to a different feather profile if you choose to. There is no other chopper I would buy.
The cutter blades come in either right or left wing, but since the banana cut feathers are symetrical, the same blade works for both left and right wing. Herb has lots of information, instructions and pictures on his website. And he is a good guy too. Check it out here:
http://herbsarchery.com/herbsfeathercutter.html Allan