For biodiesel concentrations of B5 or less, Coxreels recommends the use of our standard fueling reels. For concentrations above B5, stainless steel plumbing should be used with Viton seals and non-sparking pawls: SHF-N-525-BBN, TSHF-N-XXX-BBN, or TSHL-N-635-BBN. In concentrations above B20, Viton seals must be used along with a special hose: TSHF-N-620-BBN with the Flexwing VersaFuel Hose.