The Thermarest ProLite Plus provides self-inflating support when journeying into the backcountry. The 1.5-inch (3.8 cm) pad boasts a 3.2 R-value for added warmth in the backcountry. The diagonal-cut foam creates a lighter mattress without sacrificing warmth. Premium materials and foam provide legendary Therm-a-Rest comfort and support. The versatile self-inflating pad features the high-performance WingLock valve, which has three-times the airflow rate of the classic valve thanks to a larger opening and one-way inflation. ProLite Plus R Sleeping Mat