It's a good investment.
I bought this lumbar support for my dad in August 2016.  He has stenosis of the spine and he's not ready for surgery.  He loves it!  He's actually able to sit comfortably in most chairs with this.  It does come with a washable/removable cover.  It does not come with a strap to hold it in place on the chair but does have loops to do so.  He was able to use it on his flights to and from New York and was in less pain after the flight than before having this.  Now the material is weird and may take a few tries to position it and find the sweet spot for you.
Rating: 5 stars