Warm Note The dimensions of this mattress after inflating is about 53.94 x 34.25 x 17.72 inches (137 x 87 x 45 cm), please allow manual measurement error. We strongly suggest you measure the size of the your car backseat Before buying, in case of unnecessary returning; Please do email us via your amazon account before returning or leaving review, we're sure to help you solve it effectively, if you have any issue for this mattress for car. Most Important Operation for Avoiding Deflating 1. Please Insert the air pump to inflate the 2 layer anti-leak valve caps one by one, and be sure both valves are screwed tightly after inflating for preventing accidental air leaks. 2. If it is too soft, turn on the small inflate hole and use the medium nozzle for filling in more air for your car mattress. 3. After 24 hours of inflation, a slight natural leak is a normal phenomenon; please inflate it again depending on your desired firmness for optimal use. 4.Please protect this mattress from any sharp objects and cigarettes when using. 5.Please read the instruction of the electric pump before inflating the car air mattress. Multifunctional Inflatable Mattress This air mattress ideal for indoor and outdoor use such as camping, traveling, hiking, also used as a temporary bed prepare for your overnight guest; Or sofa air couch when you move to a new house or rental apartment. Comfortable for Traveling and Camping Made of 3 layers of sturdy wear-resistant material, ensures this air mattress completely air tight with no leaking; This inflatable air bed has been designed specially for outdoor use with unique honeycomb holes construction and 0.4 mm extra thick non-toxic PVC material which makes it more durable against the hard ground; 0.6mm flocking offer you comfortable sleep.