Diamond plated aluminum combination auxiliary fuel tank and crossover toolbox. Toolboxes include stainless steel locks to prevent tampering, and two cylinders to hold open crowned lid. Each tank comes with a rollover vent, manual sight gauge, baffles, secured fuel fill area, and drain fittings. It is the user's responsibility to comply with local, state and federal requirements pertaining to safe transportation, loading and discharging of tank contents. Not intended to be used for gasoline. We suggest using the Easy-to-install Optional Diesel Install Kit (CW# 56511, 85005, or 56512 depending on your truck model) for connecting your auxiliary tank to your truck fuel fill line. For safety reasons, the filler neck on RDS fuel tanks prevents them from being overfilled. Actual usable tank capacity is about 95% of the total advertised gallons due to fuel expansion in warmer climates. Tank meets DOT standards Not intended to be used for gasoline Made in USA | RDS Auxiliary Combo Fuel & Tool Boxes, 91 Gallon