These break-away wire links allow Jim-Buoy Life Floats and Buoyant Apparatus rafts to float free of a ship that sinks in deep water.
One side of the break-away wire link is secured to the ship, and the other side is tied to one end of the raft's 100 ft painter (the other end of the painter is tied to the raft).
The rafts are mounted on the ship such that they can float free if the ship goes underwater.
If the ship sinks in water less than 100 ft deep, the rafts stay attached to the ship by the painter - which prevents the raft from blowing or drifting away.
However, if the ship sinks in very deep water, rather than have the raft dragged down with the ship, the buoyancy of the raft breaks the wire link and the raft pops to the surface, free of the ship.
Since different sized rafts have different amounts of buoyancy, there are (three) different strengths of wire links to accommodate this.
Each wire link is tagged to identify float size it is legal for.