OBUS Forme Low-back Backrest (20% - $54.99)

Decent little backrest that I know has helped a few people with back pain, including my retired father who now spends his day professionally watching streamed content 24/7 on his iPad. The others were co-workers who got doctors notes and were able to get this covered by health insurance (USA).

For what it's worth, this was recommended independently by his PT as well as his OT.

From the site:

• Transforms ordinary chairs into ergonomically correct seating
• The S-shape of the OBUS Forme® backrest support moulds your spine into a more anatomically correct position
• Helps to enhance overall posture by supporting proper spinal alignment
• Can prevent fatigue by reducing strain and energy demand on muscles