Abstract: A flotation device for causing an article to float if accidently dropped into water has protection from being triggered unless submerged. The flotation device includes a casing, a compressed gas cartridge, a pierce head biased by compression of a firing spring, at least one trigger, a dissolvable ring, and a balloon. The at least one trigger passes through, respectively, at least one trigger orifice formed in the casing. So long as a chamfered end of the at least one trigger is held by the dissolvable ring in abutment with a chamfered trigger groove in the pierce head, the pierce head is held against the biasing force of the biasing spring. A water control feature is characterized by a rim of an end cap being narrowly spaced from the casing, thereby forming a water passage therebetween. The width of the water passage between the end cap and the casing is such as to allow water to pass therethrough to the dissolvable ring only if under hydrostatic pressure of submergence.