Outdoor lovers, you know how cold a night can be when you sleeping outdoor. Packing a heavy sleeping bag can be a hassle, but you won’t have this issue with Spark SP I sleeping bag from Sea to Summit. This sleeping bag can be packed down literally to the size of a one-liter water bottle. An ultralight bag that features compact size without sacrificing the comfort, it’s an ideal choice for backpacking, mountaineering, or cycle touring. This is by far the lightest and most compact sleeping bag from Sea to Summit, it also works great with a booster bag, you can slip inside another sleeping bag for more warmth.