Portable Diesel Exhaust Fluid (DEF) Tanks are a great option for def transport in the back of trucks & trailers. DEF is an aqueous urea solution used in seletive catalytic reduction to reduce NOx emissions on diesel engines. DEF is a high purity product and must be stored and transfer in specific tanks to maintain product quality. Diesel Exhaust Fluid Tanks are constructed with high quality polyethylene ideal for transferring diesel exhaust fluid. These tanks come ready to use with no additional accessories needed.