Personalized Mechanic Nuts and Bolts Infant Romper. Mechanic Nuts and Bolts Infant Romper - White, with "mechanic" underlined with a wrench and bedecked in nuts and bolts, are a unique gift design for professional and weekend mechanics! Meet your new favorite outfit! Keep dressing simple with this one piece, lap shoulder t-romper. Super soft and perfect for baby's sensitive skin. 5.5 oz. 100% combed ringspun cotton premium jersey (CVC Colors are 60/40; Heather is 90/10 combed ringspun cotton/polyester)