46 CFR 160.005-6 - Marking.
Each life preserver must have the following clearly marked in waterproof lettering on a front section:
(a) In letters three-fourths inch or more in height:
(1) Adult (for persons weighing over 90 pounds); or
(2) Child (for persons weighing less than 90 pounds).
(b) In letters capable of being read at a distance of 2 feet: