S = 4.76 inches, M = 5.28 inches. Ergonomic Contoured Design: Our seat cushion features a contoured shape that follows the natural curves of the human body, providing comprehensive support for your hips and lower back. This design helps distribute pressure points, improves posture, and effectively alleviates the discomfort associated with prolonged sitting. Premium Gel Memory Foam: Crafted from high-quality, cooling gel-infused memory foam, the cushion remains cool and breathable-preventing heat buildup even during extended periods of sitting-and quickly rebounds to its original shape within seconds once pressure is released. Non-Slip Base and Removable Cover: The base features a non-slip design to ensure the cushion remains securely in place on any surface without sliding. The zippered cover is easily removable for hassle-free cleaning, ensuring a consistently clean and fresh user experience. Versatile Application: Designed for universal compatibility, this cushion fits perfectly on a wide variety of standard seats-seamlessly integrating into any setting, whether in an office environment, a wheelchair, a car, or at home. Weight: 3.06 lbs.