Challenger Sealed Sleeve DC Fans Orion Fans Challenger Sealed Sleeve DC Fans provide a unique patented sealed sleeve bearing system that has a life expectancy in excess of 50,000 hours. These fans are available in a variety of sizes from 1.6' x 0.4' to 4.7' x1.5', 12VDC and 24VDC, and RPMs from 2200 to 7800. Orion Fans Challenger DC Fans are offered at a cost effective price point compared to the ball bearing counterparts.