Mercifully, gone are the days when your cold weather gear consisted of a long-sleeve cotton tee-shirt and an iron will. But if the choice of base layer options was too limited 30 years ago, it's almost too varied today. Craft makes the process of elimination very easy with their Zero Extreme Concept Long Sleeve Base Layer.Base layers should not add an irritating or lumpy layer of bulk under your jersey. Their usefulness will rest in their ability to regulate your core body temperature since therein will lie your overall success as an athlete. For decades now Craft has been developing materials intended to keep you warm in an arctic winter or cool in Saharan heat. The two fabrics which handily succeed in fulfilling these large temperature control demands are the Pro Zero and the Pro Cool, respectively. And the key to both the fabrics is how well each works to keep the body temperature neutral by keeping it dry. By merging Craft's two flagship fabrics, the Pro Zero and the Pro Cool, the Zero Extreme combines the moisture wicking genius of the Pro Zero with the moisture transference of the Pro Cool. This means that as you sweat, the Zero fibers pull the moisture away from your body while the Cool fibers pull the damp to the outer layer of the shirt. Once the moisture reaches the outer layer, the weave of the Cool fiber promotes air circulation away from the skin which dries the fabric without cooling you off at the same time. The Zero Extreme also incorporates an antimicrobial treatment which prevents fabric odor from setting in. The Craft Zero Extreme Concept Long Sleeve Base Layer has been designed to regulate your body temperature in whatever zones require it. The seamless torso has an ergonomic fit, but doesn't pull uncomfortably at the armpits since the thin, lightweight fabric is also extremely elastic. It will hug, not cling to your body, and the flatlock seams succeed in making this base layer an ideal second skin. The Craft Zero Extreme Concept Long Sleeve Base Layer comes in Silver/white and is available in sizes Small though XX-Large.