9 Testing and measuring equipment used in sampling and testing petroleum, petroleum products and chemicals, namely, tank gauging and measuring equipment in the nature of petroleum and chemical gauges; graduated cylinders; hydrometers; moisture testers, namely, electronic sensors for measuring the amount of moisture in oil tanks; testing sample collection equipment, namely, tank samplers for use in diagnostic testing, not for medical purposes; thermometers, not for medical purposes and accessories in the nature of batteries; oil thieves in the nature of sample containers for the purpose of examining and testing crude oil before it is shipped to a refinery; control valves for regulating the flow of gases and liquids; density determination equipment, namely, electronic sensors for measuring density; water and water/oil emulsion determination equipment, namely, electronic sensors for measuring the emulsion level of water and oil; devices for determination of volume for custody transfer of liquid products, namely, electronic sensors for measuring volume of liquid products; temperature reference equipment, namely, temperature sensors