Russell Athletic Essential Muscle Tee The Russell Athletic® Essential Muscle Tee offers the comfort of cotton combined with the benefits of performance. This lightweight crewneck sleeveless T-shirt delivers the comfort, style, and performance to fit your active lifestyle. 4.75 ounce. 60% cotton/40% polyester. Oxford: Oxford 47% cotton & 53% polyester. Dri-Power® Moisture Wicking Technology. Odor protection. Pad print label. RUSSELL ATHLETIC heat sealed label on bottom left front. Crew neck. UPF 30+, provides protection from the sun.