The Seraphin® 5 Gallon (20 Liter) Vapor Retention Prover (VRP™) is a graduated neck, bottom drain vessel built to N.I.S.T. Handbook 105-3 Standards, OIML R-120, Measurement Canada and API Manual of Petroleum Measurement Standards Chapter 4. Using Seraphin's® 5 Gallon (20 Liter) VRP™ can speed the job of calibrating multiple fuel dispensing units, while at the same time, enhancing safety and productivity. It eliminates the need to carry heavy measures filled with fuel while tripling the amount