(a) The indicating means shall consist of a calibrated gauge rod and level indicating plate.

(b) The rod shall be of rigid design, made of stainless steel smoothly finished with the probe end tapered to one half inch, and when properly seated in position, shall touch the bottom of the holding tank being measured. The rod shall be graduated throughout an interval corresponding to the range within which readings of the cherry level are to be made.

(c) On a rod the spacing of the graduation center to center shall be not more than.0625 (1/16) inch and not less than.03125 (1/32) inch. The graduation shall be not less than.005 inch in width and the clear interval between adjacent edges of successive graduations shall be not less than.015625 (1/64) inch. The graduations shall be designated in inches, 0.5 inches, 0.1 inches, and 0.02 inches.

(d) The level indicating plate assembly shall consist of a rigid plate and a slider tube designed to move up and down the calibrated gauge rod. The rigid plate shall be a perforated round disk of stainless steel, 10 inches in diameter, with the perforations not exceeding three eights of an inch in diameter. The plate shall be permanently attached to the slider tube. The slider assembly shall move freely on the gauge rod without slope and shall weigh four pounds, plus or minus one tenth of one percent.