Review on BackJoy SitSmart Posture Core Seat Cushion: Ultimate Support for Lower Back Pain Relief, Improved Posture 🪑 | Ideal for Car/Office/Hard Surface/Desk Chairs | Waterproof & Portable | Onyx Color | Designed for Adults by Brent Henderson

The only useful place to use this plastic thing is on the floor. I've tried using this on semi-hard, hard and non-hard surfaces and the plastic is quite brittle and sometimes kinked. Of course it's plastic or rubber but I thought it must be strong to support and stabilize your back? If you sit on it incorrectly or deviate even an inch from the center, you risk falling. It's like riding a bull in a rodeo show. As much as I love the design and the hassle free shipping company, I really don't like this product. I could list more downsides to this design, but I'm already tired of thinking about those rubber slides. Thank you for the smooth and fast shipping, not much for this product.