BNWT Under Armour short-sleeve t-shirt in bright red, XL. Retails between £25-£35. The Under Armour Performance t-shirt in size XL is a solid red short sleeve shirt with a crew neck and pullover closure. Made from polyester, this activewear t-shirt is machine washable and features the Under Armour logo as accents. The t-shirt is part of the Under Armour HeatGear product line, designed for sports and gym training activities in the summer season. It offers a regular fit for men who are looking for a comfortable and performance-driven top.