These locking tab rings are used on the female connector of a shore power cordset and twist (Easy-Lock) onto the vessel's shore power inlet (boat side) to make a watertight seal with just a simple 1/8 twist.
This Marinco 100EL 30A power cord Easy Lock Ring (as well as their 500EL 50A power cord Easy Lock Ring) can only be used on Marinco "Easy Lock" inlets of the appropriate amperage.
The Easy Lock feature is found on all Marinco inlets manufactured after 1995 (note the "EL" in the inlet's part number).
The convenient Easy Lock feature is exclusive to Marinco, and these rings can not be used on other manufacturers' inlets.
Easy Lock sealing rings can not be used with the Marinco 110R 30A threaded sealing collar system for making a waterproof connection between a power cord and an adapter.
Made of black Lexan®.