Sea to Summit Thermolite Reactor (Extreme) Mummy Bag Liner
We had the Thermolite Reactor liners and the kids had Reactor Extremes. We would probably choose the extremes for ourselves in the future because they were warmer but we were fine the whole trip. These kept our sleeping bags a little cleaner because we were easily able to wash the liners when we did laundry. On hot nights we slept just in the liners.