Haven Well Within. A thoughtful collection of lounge, sleep, home, and lifestyle essentials — and your trusted resource for all things wellbeing. Just-right, lightweight comfort for cozy nights under the duvet. This smooth, classic sleep tank is made from TENCEL™ Modal fibers — for that cool, easy feel you love. TENCEL™ Modal fibers are mainly manufactured from beech wood, sourced from sustainable forests in Austria and neighboring countries. Beech wood forests are a natural and renewable source of raw material. A big share of the wood used at the Lenzing site comes from Austria, harvested from certified and controlled sources following the stringent guidelines of the Lenzing Wood and Pulp Policy. Moreover, wood and pulp used by the Lenzing Group comes from sustainably managed forests. TENCEL™ Modal fibers have earned United States Department of Agriculture (USDA) BioPreferred® designation.