This one did not work in a work chair, a lounge chair, or in my driving seat. It was too hard. There was no place to rest my tailbone. It may work for someone without a coccyx injury, but it only hurt mine more. Plus, this thing is super heavy! It does come with a handle and the cover is removable for washing.
This one also was too hard and didn't provide a place for my tailbone to rest. I haven't found a chair to use it on that is comfortable. Again, this probably is more comfortable for someone who isn't in pain. The cover is super soft and the interior is memory foam.
This one does provide some relief. I use it on my office chair where I sit to type. It has a zipper so the cover may be removed for cleaning. The top is sort of velvety and the bottom is made of a gripper-type material so you don't slide around in your chair. My cat likes to nap on this one and it does attract cat hair, so...
I added a lumbar support to the chair and it is reasonably comfortable. At least if you have to sit stick-straight up in your chair there is some relief for your back as well as your butt.
It has a gripper bottom and is fairly comfortable on my office chair. I put it on my sewing chair for extra padding, but it's not a good solution for the tailbone injury.