drag slotUsage: This chart will allow you to calculate the gear ratios or rollout for Slotcars.Only available ratios will be shown based on what size and pitch gears are available (the white spaces withReplacement power transistor for drag modules and controllers. New 3 transistor desn has 50% more power handling capacity then our old desn. Instructions included. $22.50. DD839: Drag Power Transistor. Repair kit for the 4 transistor