Sitting on a hard wooden or metal chair—or even a soft, ergonomic model—can put a lot of stress on the lower back. That’s where a good seat cushion comes in. We’re not talking about the ones that fluff up the sofa, but rather models that are specially designed for comfort and proper posture. You’re probably better off with a contoured U-shaped seat cushion rather than a flat one, since it relieves pressure on the tailbone while contributing to good posture. In addition to shape, you’ll also need to choose between foam and gel filling, and the thickness of the cushion. Here’s how to choose the form that’s right for you.

Great Value

This set comes with a separate waterproof layer to protect it from messy spills. U-Are

Memory foam cushions better accommodate the contours of your body, and they provide a stable sitting surface. However, they also trap heat, which may get uncomfortable. Over time, they tend to sag too. Gel cushions come with a host of advantages—they’re cooler, more durable and easier to clean. A cushion with gel-infused memory foam combines the best of both forms.

Extra Thick

The zippered cover is washable in warm water on a cold cycle with a cold-water rinse. 5 Stars United

Seat cushions are generally between one and four inches thick, so there is a lot of room for variables. A cushion that’s too thick can put undue pressure on the spine, as it pushes your weight toward the front of the seat. Still, thicker may suit you better for extended periods of sitting and long drives.

Works On the Go

A hypoallergenic, breathable mesh fabric helps keep your back cool and dry. Everlasting Comfort

Back cushions work to relieve both upper and lower back pain. They promote good posture by discouraging the inclination to hunch forward while working on your laptop. You can also bring them along for car rides to help keep you upright yet comfortable at the wheel.