Anyone know what this is?

[Chris Perkins]

I've had this mysterious coin for a few years, sitting around unidentified.

Anyone know what it is? It came with a sticker that reads '3rd SEN'. I have no idea if that makes any sense to someone, or even if the sticker should have belonged to something else. It's 3.3g and about 18mm.

Indian or somewhere in that region?

[Nick]

Looks pretty similar to this.

[Chris Perkins]

I think it looks exactly like that! Thanks, that's solved it.