What did Ferrucio Lamborghini sell before he started producing cars?

Explanation

Although most people today associate Lamborghini with their sports car, the company Automobili Lamborghini S.p.A. was founded in 1963 as a side project to Ferrucio Lamborghini's very successful tractor factory in Bologna, Italy. He also made money by producing oil and gas boilers, ovens, and airconditioning systems.