Each stationary tank, vat, cask or other container used, or intended for use, as a receptacle for wort, beer or concentrate produced from beer shall:
(a) Be durably marked with a serial number and capacity; and
(b) Be equipped with a suitable measuring device. The brewer may provide meters or other suitable portable devices for measuring contents of tanks or containers in lieu of providing each tank or container with a measuring device. (Sec. 201, Pub. L. 85-859, 72 Stat. 1395, as amended (26 U.S.C. 5552))