The OML Pinger Mk. II is a subsurface omni-directional acoustic beacon. It is an inexpensive form of insurance for mooring strings that may be worth hundreds of thousands of dollars. Pingers of different frequencies at the top and bottom of a mooring allow you to quickly determine whether a mooring is still in place and intact. In the event of an acoustic release failure, the pinger may be the only way to locate the mooring, particularly if it has been hit or moved by fishing or shipping activity.