Super Rare c.1794-1798 Regiment of Artillerists & Engineers Coat Button AY7 in Albert's

Super rare, c.1794-1798, Regiment of Artillerists & Engineers coat button. This is button AY7 in Albert's. The front has REGt USA & E with a cannon and stack of cannon balls between them. This button was dug near Pepperell, Mass. and shows ground action. This is the only dug AY7 I have ever seen. Measures 20.5 mm's in diameter. $265