Engel merino organic wool/silk sleeper is perfect under a sleep sac. Soft and lightweight merino wool/silk is breathable and adds a fine layer of warmth without heat buildup making it the ideal base layer for a comfy night.
Wool/Silk is a good blend for sensitive skin. Silk actively balances temperature, giving warmth when it is cold and cools down when warm. Wash by hand or machine washable on gentle cycle in warm water.