The Assos ThermoBooster P1 is a versatile, packable thermal layer designed for high-intensity riding, now featuring pockets for added functionality. It can be worn as a jersey in cool conditions or as a midlayer for extra core warmth in the coldest, toughest weather. The new thermal fabric is a highly elastic warp knit that hugs your body&&';;s contours with an aerodynamic fit, offering breathable comfort even during intense efforts. If the temperature rises or your ride heats up, the ThermoBooster P1 easily packs down to the size of a rain jacket, fitting neatly into a jersey pocket. Its adaptable design makes it perfect for any season-wear it over a base layer or summer jersey in spring and fall, or under stormproof gear for added warmth in deep winter.