Check the listing for details. API Diesel Fuel Hydrometer Set, Better MPG, Made in USA, A.P.I., Quality. Condition: New. Listed at 119.99 USD. Test Your Diesel Fuel Quality... You may be surprised! Many people do not realize that the density of your diesel is directly proportional to your fuel mileage, horsepower and overall engine performance... Features: Heavy Duty, Industrial Grade 29 - 51 A.P.I. Scale (Quality Diesel should be approximately 35 A.P.I.)Built in Temperature CompensationHigh Quality Fuel resistant rubber partsAll in one design for minimal mess Quantity Discounts Available Free shipping to the lower 48 states only. If you have any questions about our products, message us. We have trained technicians waiting to answer your questions! Our hours of operation are Monday thru Thursday 7 AM-5 PM EST. HAND-MADE, PRO-GRADE & USA-MADE Check out our eBay store for other great products!