Chinese cash

Hello, what is this coin, is it fake?

Weight: 3 grams 

 thanks

Numisdoc china : emperor 嘉慶, Jiaqìng,1796-1820

Boo Dong

And in the directory is : Boo Dung (well they should put the same word …)

N#45604

Then 4 varieties (if it's too simple, it isn't chinese …)

It's the first variety Hartill#22.547 (just trust me, it's the standard writing of Dung)

Thanks