If you are referring to the twin gears on the reverser, far as I know there is only one source...and being so is also the best price.
I would venture to say quality is beyond reproach.
you should be able to turn up a thread from a few weeks back about them...but here is what I believe you are asking about-
Ps- might seem expensive but really it's not, probably much cheaper than you could make yourself if you value your time, and it's not like you change them like socks.
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