eChairParts is legit!! I was initially skeptical, I had never heard of them.
They are awesome.
I bought an ErgoChair 2 only to discover it did not go high enough for me. I did some research and found out a gas cylinder was the answer to make it work. I bought one from Amazon and it made my chair into a bar stool no good.
I found their site. See the picture. I told David what I needed. He taught me how to measure it, gave him the results, and then he told me the part to get. And it worked. I needed something super specific and he had it and advised.
This has been one of the best customer support experiences I've had. I got the part and have been using it for over a week and it's fantastic. Highly recommended!