The pinnacle of light and stable self-inflating comfort, the Therm-a-Rest Prolite Apex Ultralight Self-Inflating Backpacking Pad with WingLock Valve offers unrivaled warmth without adding excess bulk or weight to packs. The ProLite Apex has an R-value of 3.8 thanks to StrataCore construction, allowing for comfortable three-season backcountry adventures (R-value measures the material's ability to insulate; the higher the R-value, the warmer the sleeping pad). Offering the best warmth-to-weight ratio for self-inflating pads, the unique construction uses a continuous layer of thermal foam nestled between alternating ridges of air and foam. The 2-inch thick sleeping pad is built with thermal self-inflating foam; top it off with a few breaths after the foam expands. Equipped with a dependable and rugged WingLock valve, the pad inflates three times faster than a classic valve and features lightning-fast deflation. The ProLite Apex includes a stuff sack to protect the pad when it's packed down. Available in three sizes: Regular measures 72x20x2 inches inflated, packs to 11x5.2 inches, and weighs 22 ounces; Regular Wide measures 72x25x2 inches inflated, packs to 11x5.5 inches, and weighs 28 ounces; Large measures 77x25x2 inflated, packs to 13x5.5 inches, and weighs 30 ounces. Manufacturer's limited lifetime warranty.