When camping outdoors, at night the temperature will drop very low, limbs will be cold if sleeping under such conditions. With toe warmer and hand warmer the problem will be solved very effectively. When sleeping in a sleeping bag, you must remember that the sleeping bag keeps us warm by retaining the amount of heat our body emits. So the more you wear your clothes, the more heat your body gets trapped in your clothes, doesn’t circulate effectively and breaks the sleeping bag’s warm-up mechanism, the more you feel cold. So a thermal underwear will help you sleep more comfortable and warm.