Specifically designed for the most challenging sanitary and storm lines, Cobra Mainline Crawlers are powerful, rugged and dependable. The unique belt drive system and automatic freewheel clutch make Cobra Mainline Crawlers decisively superior in performance. The Automatic Freewheel Clutch connects an electric tooth clutch in parallel to the crawler motor. When voltage is applied or removed, the clutch automatically engages or opens. Other crawlers use mechanical clutches, requiring users to drive the crawler into a freewheel condition, a time-consuming productivity sink.