Providing warm, dry next-to-skin, moisture wicking performance, the Arcteryx Rho LT Zip Neck for Boys uses lightweight synthetic fibers to move moisture rapidly and a silver ion treatment to remove odor during any endurance endeavor. An ideal warmth-to-weight ratio base layer for backcountry adventurers, the clean detailed Rho LT Zip Neck is Built for year-round use. No-lift underarm gussets that let you raise your arms without your shirt going for a ride while the soft and form-fit of the Rho LT fleece is Great for wearing alone or layering up.