Section 149.331 - What are the requirements for hybrid personal flotation devices?(a) The operator must ensure that the use and stowage of all commercial hybrid personal flotation devices (PFDs) used as work vests comply with the procedures required for them in 46 CFR 160.077-29 , and all limitations, if any, marked on them.(b) All commercial hybrid PFDs on the deepwater port must be of the same or similar design and must have the same method of operation.