I love my cushion - in fact, I have a second one in my other house, and a third in my living room chair. It is the Cushion Lab Pressure Relief Seat Cushion. They are kind of pricy, but mine are over 2 years old and still work perfectly. It was recommended by my PT, and I just looked for the best price I could find - it wasn't Amazon, but I don't know where I found it. I probably just Googled for it.
It looks kind of ugly on my furniture, but it makes so much difference to my achy body that I don't care.
Sue
PS My daughter trued to take one of mine home with her after trying it.