If it were a Powder flask,what is the tab for then?I have never seen that on any flask
All we truly see on the back is the depressed design between the eagle's neck and wing, which is actually appearing raised when viewed from the reverse side. It's sort of an optical illusion, that plays tricks on the eyes no doubt. Take a second peek at the relic and let me know what you think. 
Montana Jim said:kuger - I dont think that's a tab, just a little piece breaking off.