Weighing only 12 ounces, the Sea to Summit Spark Spl Sleeping Bag brings the comfort without the weight whether you're an ultralight backpacker, an adventure racer, a touring bicycler, or an alpine climber. Primarily focusing on giving you the lightest bag out there, Sea to Summit stuffed the Spark Spl with 850+ down for the best possible warmth-to-weight ratio that can still keep you nice and toasty in temps down to 45F. Going beyond just being ultralight, Sea to Summit's Ultra-Dry Down treatment also helps this bag resist moisture to enhance your comfort regardless of the conditions. The Spark Spl has a contoured mummy shape to closely fit your body while you sleep. Its full hood wraps around your head to eliminate the possibility of waking up with freezing ears, and the 1/2-length zipper on the left helps maximize warmth when the temps drop. If you find yourself in colder conditions, the SpI can be utilized as an ultralight sleeping bag liner in another sleeping bag to keep you warmer through high alpine treks or winter camping. Finally, the Spark compresses small so you're able to stuff your pack with a few extras even if you are a minimalist.