This hard-bottom back seat extender expands your car, SUV, or truck's backseat by about 40%, giving your dog a wider, flatter space to lie down instead of sliding around on the seat cushions. A honeycomb board base supports up to 350 pounds and stays rigid and flat, preventing the sagging or collapsing you get with soft hammock-style covers. Seven layers of protection, including waterproof, scratch-resistant 600D Oxford cloth on top, hold up against claws and everyday wear, and the cover can be removed and washed to keep your car clean. A detachable mesh window lets your dog watch the road and interact with you, helping reduce car anxiety, while two storage pockets keep essentials within reach. A safety belt is included for extra security, and at 53 x 24.8 inches it fits neatly across most back seats.