What is this? 4-20

[remrogers]

[bambam]

One of Barry's sex toys ?   

[pitw]

Well I'd say it's for holding a nut[or bolt], why it is brass I have no idea.  Maybe for use with fammable/explosive materials.

[remrogers]

A brass "keeper", it held a nut in place on an engine shaft of the ship Wolverine, salvaged in 1949.

USS Wolverine (IX-64)

Built at American Shipbuilding Company in 1912 at Wyandotte, Michigan, the side-wheel excursion steamer, SS Seeandbee was acquired by the U.S. Navy in March 1942 for services during World War II.  Renamed Wolverine, she was converted to a training aircraft carrier and received the designation of IX-64.   During the war, she trained hundreds of pilots on Lake Michigan.   Upon the war's conclusion, Wolverine was decommissioned in November 1945 and was sold two years later for scrapping.

https://www.history.navy.mil/content/history/museums/nmusn/explore/photography/ships-us/ships-us-w/uss-wolverine-ix-64.html