Designed to fit most standard wheelchairs, these cushions provide optimal pressure relief and comfort for all-day sitting. Both cushions work by distributing the patient's body weight evenly. The gel cushion gives patients an especially stable feeling, because the gel is similar to a patient's adipose tissue (fat layers). And because the gel is very thick, it minimizes leakage, even if the cushion is punctured. Both cushions are very durable and easy to clean. Gel cushion, 18" x 16 1/2".