33 CFR 67.10-1: -1 Apparatus requirements.

The sound signal required by §§ 67.20-10, 67.25-10, and 67.30-10 must:

(a) Have its maximum intensity at a frequency between 100 and 1,100 Hertz;

(b) Sound a 2-second blast every 20 seconds (2 seconds sound, 18 seconds silence) unless otherwise authorized by the District Commander;

(c) Have the rated range required by § 67.20-10, § 67.25-10, or § 67.30-10;

(d) Have a height not exceeding 25 feet;

(e) Have not more than eight sound sources;

(f) Be approved by the Coast Guard under § 67.10-15; and

(g) Be permanently marked with:

(1) The date of Coast Guard approval;

(2) The manufacturer and date of manufacture;

(3) A model designation;

(4) The approved range; and

(5) The power necessary to comply with the provisions of paragraph (c) of this section.