I've been slouching for years at the desk and as much as I try to sit up straight, I always forget and end up hunching forwards. In the last few months I've been having a lot of trouble with back pain so all the slouching has been very noticeable and it actually makes the back pain worse. I've been using various cushions to try and get lumbar support but they flatten quickly and start feeling very uncomfortable.
Enter the lumbar roll. I got it because it was inexpensive and thought it would provide good lower-back support while forcing me to sit up straight. It definitely does the job! The lumbar roll is firm so it's not going to flatten quickly. It has a long adjustable strap big enough to fit around one of those big leather executive office chairs (which is what I have). I am quite small myself and was worried that the lumbar roll might be too bulky for me but I actually found that it provides perfect support in the curve of the back and I have a much better seating posture now. I would definitely recommend the cushion for anyone who is having back problems or just wants to correct the way they sit at the desk.
Also a quick note, the cushion is grey in the picture but I actually received it in black - my chair's black so this was a good thing, but just thought I'd mention it incase you had your heart set on the grey.