Ten and a half inches is all the Basin + Range Clutch Air Mat asks for in the pack or trunk, though it stretches out to a full 76 inches once the valve does its work. We built the bottom layer tougher than the top, since rocky, uneven ground wears out a pad faster than anything else it'll face on a backpacking trip. What Our Gearhead(R) Experts Are Saying:"I've had mine set up and full before my hiking partner gets the tent stakes in. The reinforced bottom hasn't shown a scuff yet, even off gravel bars I probably shouldn't have picked."