The self-inflating ProLite Apex camping mat achieves unrivalled warmth without adding excess weight to your pack. Featuring a StrataCore construction, a continuous layer of thermal foam is sandwiched between alternating ridges of air and foam to yield the best warmth-to-weight ratio possible. For personalised sleeping comfort, once inflated top up with a few breaths to increase firmness. Featuring the new WingLock Valve system, it maximises airflow for easier inflation and quick deflation. Therm-a-Rest Prolite Apex Regular Camping Mat - Heatwave