While doing some searching on ebay, the "why pay more?" store, I found that quite a number of trimmer pots are not what they appear to be.
Here you have Borton, Baoshi, Bonens, Barons, Bochen, and Borans trimmers.
What you get is up to you, but the original product can be obtained from any number of reputable distributors for a relatively modest sum. I sure didn't think it was worth gambling an amplifier worth several hundred dollars by trying to save a couple of bucks.