With the increased use of Natural Gas as a fuel, higher natural gas prices, and the new federal regulations, buyers and sellers of natural gas are seriously looking at ways to improve their natural gas. measurement and reduce the unaccounted for natural gas. An error in measurement of only one tenth of one percent (0.1%) on 100 million standard cubic feet per day of Natural Gas selling at $3.00/ MCF will cause an over or under billing of $109,500.00 in one year. This will more than pay for a proving system. The BTU in one barrel of oil for example is equivalent to approximately 5,600 cubic feet of natural gas. At $3.00 per thousand cubic feet, the natural gas equivalent of one barrel of oil costs $16.80 or more than the cost of a barrel of oil. In the petroleum liquid industry no custody transfer liquid measurement system would be complete without a method to prove the meter, either as part of the equipment or have connections provided on the measurement skid to connect a portable prover