Features LIFAA(R) MERINO Lifa Stay Warm technology Flatlock seams for extra comfort Elastic in waist for perfect fit and freedom of movement Construction that prevents twist of the elastic band Gusset in crotch for freedom of movement Solution Dyed Main Fabric The wool in this product is Responsible Wool Standard wool, certified by IDFL (TE-99972454). Composition Shell: 57% Merino Wool, 43% Polypropylene