I have been unable to dig up much information on this piece of military surplus. From my research it is some type of tool used in military aircraft maintenance. It is threaded on the outside with machined surfaces on the front and back. The inside is cast and curved with three "lugs" presumably to turn the threaded deviced. Item appears to be solid brass (just my educated guess) and weighs about 4lbs 14oz. It is about 7 3/8" across and about 1 9/16" thick, with threads about an inch thick. The smaller ID is about 5 1/2" across. Don't be afraid to throw me an offer. 

NSN(short): 5120007341922

NSN(long): 1RW 5120-00-734-1922 SX

FSCM87641

Mfg Part No: SWE845402

Units appeared to have been manufactured in 2013.

Unit is sold as-is with no warranties from the seller, express or implied. 

Returns are accepted within 14 days with return shipping paid by the buyer. NO RETURNS IF THE ITEM HAS BEEN USED IN ANY WAY. Thanks!