W. Va. Code § 47-1-4

The system of weights and measures in customary use in the United States and the metric system of weights and measures are jointly recognized, and either one or both of these systems shall be used for all commercial purposes in the state. The definitions of basic units of weight and measure, the tables and measure, and weights and measures equivalents as published by the national institute of standards and technology are recognized and shall govern weighing and measuring equipment and transactions in the state.

The specifications, tolerances and other technical requirements for commercial, law enforcement, data gathering and other weighing and measuring devices as adopted by the national conference on weights and measures and published in national institute of standards and technology handbook 44, "Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices" and supplements thereto or revisions thereof, shall apply to weighing and measuring devices in the state, except insofar as modified or rejected by legislative rule.