46 CFR 160.049-6 - Marking.
(a) Each buoyant cushion must have the following information clearly marked in waterproof lettering:
(1) In letters that can be read at a distance of 2 feet:
(2) In letters that are distinctively set off or larger than all other marking, and are at least one-fourth of an inch in height:
(b) Waterproofness of marking. Marking for buoyant cushions shall be sufficiently waterproof so that after 72 hours submergence in water, it will withstand vigorous rubbing by hand while wet without the printed matter becoming illegible.