Wouldn't stay up on my Chair
The cushion is much softer there others I have used the past, but beware that if you office chair as any slant on the sides, it will not stay put.  It does have a nice thick strap, but I have hard plastic side.  It would not stay in place.  If you have cloth or leather sides that the strap and grip into, it is probably no issue.
Rating: 3 stars