Personalized Mechanic Nuts and Bolts T-Shirt. Mechanic Nuts and Bolts T-Shirt - Gold, with "mechanic" underlined with a wrench and bedecked in nuts and bolts, are a unique gift design for professional and weekend mechanics! Everyone loves our Custom T-Shirts! Wardrobe essential for looking good, 24/7. 5.0 oz., pre-shrunk 100% cotton. Seamless 1x1 rib collar. Shoulder-to-shoulder taping. Double-needle stitched sleeves, bottom hem and front neck. Note: greys are a cotton/polyester blend.