RotopaX 2 Gallon DEF Container GEN 2Modern diesel trucks equipped with Selective Catalytic Reduction (SCR) systems require Diesel Exhaust Fluid to run cleanly and legally and running low on DEF in a remote area can shut your truck down just as effectively as running out of fuel. The RotopaX 2 Gallon Diesel Exhaust Fluid Container GEN 2 gives you a mount ready DEF reserve that fits into your existing RotopaX setup without any additional hardware or brackets. Two gallons of DEF on board