43 C.F.R. § 3175.43
(a) A transducer of a specific make, model, and URL is approved for use in conjunction with differential meters for high-volume or very-high-volume FMPs if it meets the following requirements:
(b) A transducer of a specific make, model, and URL, in use at an FMP before January 17, 2017, is approved for continued use if: