Lululemon Metal Vent Tech 1/2 Zip lightweight long sleeve in a ventilated mesh construction that is designed for training. Its lightweight fabric is sweat-wicking and breathable with reflective detail and four-way stretch. It is in great preowned condition. Size M The size tag was removed. Size confirmed by imprint in hem. Length: Approx. 29" Armpit to armpit: Approx. 20" Measurements are approximate.