These life lines were fitted to life jackes and pressure jerkins as detailed below. They consiated of a cord, and wooden toggle.
This is a snapshot from 1965 showing the applicable life jackets then, but more jackets and pressure jerkins will have used this life line since.
Quote:
Ref. No Nomenclature Detail 22C/1739 LIFELINE and TOGGLE, 250 breaking strain Component of jackets, lifesaving, aircrew Mk. 3, Mk. 4, Mk. 4A, Mk. 7, and jackets, lifesaving, passenger.
This lifeline is shown taped to the lifting beckets of a pressure jerkin, with the end of the line tied around the backet. Installation on life jackets is the same.