This thermal all-in-one is an essential piece to have on hand for those extra chilly days. The close-fitting, long-sleeved design is great for layering under clothes, and also looks styish on its own thanks to the popper fastenings running from the round neck. Featuring our extra-warm thermal Heatgen™ technology, the lightweight fabric feels soft against the skin, and added stretch allows for extra flexibility. M&S Collection: versatile styles in modern shapes with unique and playful details.