Electrifying ‘80s style goes all in on the Evo Lightning Muscle Tee. Its cotton jersey build is vintage washed for a well-worn vibe with a rib-knit neckline to help keep its shape. A surge of allover graphics gives this men’s sleeveless t-shirt a look you can feel. Know the history—the Evolution® or “Evo” Engine featured here debuted in 1984. Its all-aluminum architecture was a quantum leap in design and reliability for Harley-Davidson.