You've never worn a Merino base layer like this. We use a unique fabric construction method to place polyester fibers against your skin to improve wicking and Merino facing the jersey for temperature regulation and odor control. The 18.5-micron Merino is responsibly sourced while the polyester is spun from recycled water bottles. The polyester also increases the base layer's durability. The short sleeves feature a set-in construction for a versatile next-to-skin form fit. Features: Transfer Merino fabric combines wool and recycled polyester for sustainable technical performance. Unique plated fabric construction places polyester next to skin and merino on the exterior for superior moisture transfer and thermal regulation. Made using fine 18.5-micron merino wool for superior comfort. Recycled Repreve(R) XS Polyester technical fibers are made from recycled plastic water bottles. Set in sleeve construction for easy layering and versatility.