The Aero Wool Merino Blend Hooded LS Tee provides lightweight core warmth using advanced Active+ Insulation inspired by aerospace materials. Designed for long-distance runners, it includes internal pockets for secure, bounce-free storage of up to six energy gels and doubles as a stow sack. The vest compresses easily with one hand and features an adjustable hem to block drafts, making it an efficient, packable layer for race day or active pursuits.