Telephonics Corp. has won a $21.1 million contract to deliver devices to the Navy that help forces determine which aircraft are friendly and which are hostile, the Department of Defense announced.

The contract calls for Farmingdale-based Telephonics to deliver up to 46 identification friend-or-foe interrogators and mounting trays to the Navy.

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The contract also calls for delivering up to 12 mounting trays for the Australian government and up to 200 hours of engineering and technical support.

The work for the Navy accounts for $16.3 million, or 77 percent, of the contract, while the segment for Australia accounts for $4.8 million or 23 percent.

The work will be performed in Farmingdale, according to the Department of Defense, and is expected to be completed in March 2019.

Telephonics, which employs about 1,000 people on Long Island, is a unit of Manhattan-based Griffon Corp. On Friday, Griffon's shares closed at $16.83, down almost 3 percent. In early trading Monday, they were up 30 cents, about 1.8 percent, at $17.13.