Orion’s Challenger Series fans now feature a unique patented sealed sleeve bearing system that has an exceptionally long life expectancy of more than 50,000 hours at 25°C (L10). MTBF is in excess of 200,000 hours. The new sealed sleeve fan technology retains lubricant by using metal foils that serve as a guard to redirect and recycle the lubricant. The fans were developed in response to a continuing demand for fans with a wider temperature range and longer life than sleeve bearing fans, but at a lower cost in comparison to traditional ball bearing fans.