Automatic and Manual Inflatable PDF vests from Mustang Survival and others. Our selection of lifesaving vests are made for the industrial, commercial and professional use. Vests designed for extreme environments using the best technology available. What is it about Hydrostatic Inflation Technology that makes it preferred across diverse industries and environments? Exclusive to Mustang Survival in North America, Hydrostatic Inflation Technology is the most reliable inflation system available. All Mustang Survival PFDs with HIT™ will only inflate from hydrostatic water pressure when submerged under 4" or more of water, or when manually activated. High winds, humidity, stormy conditions, big seas, splash or spray will not affect the performance or integrity of a Mustang Survival HIT™ PFD.