Transparent plastic cylinder mounted between machined aluminum end plates and surrounded by stainless steel safety guard. Density and relative density measurements of light hydrocarbons, including Liquefied Petroleum Gas (LPG), are used for transportation, storage and regulatory purposes. The measurement is made by floating a thermohydrometer in a sample that has been introduced into a pressure cylinder. Use together with ASTM 310H Thermohydrometer to determine density or relative density of LPG and light hydrocarbons. Equipped with inlet, outlet and vapor vent valves for admitting sample and purging cylinder. End plates have positive sealing Buna-N O-rings and are joined by sturdy steel support rods. Top plate detaches easily without tools for insertion or removal of thermo-hydrometer. Safety relief valve prevents unsafe pressure build-up inside cylinder (200psi). Mounted on a finished steel base. Conforms to the specifications of: ASTM D1657; GPA 2140; IP 235; ISO 3993. Shipping weight: 8 Lbs.