This is Manufacturers Part #725-1BD-A1-1. Serial Number 679
Label reads:
Pioneer Central Div. Bendix Aviation Corp. Buaer U.S. Navy Indicator Turn & Slip Air Driven Rating 2 IN HG Type MD-2 Stock No. RN6619-663-4116-VIYT AND DRAWING NO. AND 10403 1725-1BD-A1-1 MFRS PART NO. ORDER NO. N383 17-383 43214A SERIAL NO. 679
Unknown working order. Measures 2-1/4" round x 5" tall.