Stratosphere 5.5Lightweight and compact, the Stratosphere 5. 5 boasts a superior warmth to weight ratio, making it a versatile all mountain sleep mat which is highly insulating yet has a small enough pack size to take on all your trekking, climbing and backpacking adventures. The recycled Stratus R insulation is designed to trap air and reduce heat loss through convection, helping to maintain your temperature when the mercury drops and ensuring you recharge ready for