While being the world's largest industrial gas supplier may sound boring, that's exactly what Airgas ( ARG) is going for. Boring business, boring name -- and anything but boring performance. In the last year, ARG has rallied more than 30%, offering investors 5 times the stock gains that the broad market has delivered. Airgas supplies everyone from industrial manufacturers to hospitals with gases such as oxygen, nitrous oxide, and acetylene, in addition to complementary hard goods such as welders and eye protection. But as the firm's name implies, gas is ARG's bread and butter. Because gas is relatively low cost (compared to customers other overhead items), the firm has considerable pricing power. Coupled with the surprisingly high returns generated from renting out gas cylinders, ARG has a cash-generation machine at its fingertips. Historically, the packaged gas business has been extremely fragmented. Airgas' huge acquisition history has helped the firm establish itself as one of the few firms big enough to handle national accounts. That improved competitiveness should help this "boring" Rocket Stock deliver higher returns than smaller peers. To see all of this week's Rocket Stocks in action, check out the Rocket Stocks portfolio at Stockpickr. -- Written by Jonas Elmerraji in Baltimore.