33 C.F.R. § 175.21
No person may use a recreational boat unless each PFD required by § 175.15 is—
[CGD 81-023, 55 FR 32034, Aug. 6, 1990, as amended by CGD93-055, 61 FR 13926, Mar. 28, 1996; USCG-2013-0263, 79 FR 56499, Sept. 22, 2014]