Trade chunk o' stainless for chunk o' steel

[ARC-170]

I have a piece of what I'm pretty sure is stainless (non-magnetic, hard to machine). It is 2" x 2.1" x 2.8" with a little "tail" that is 1.7" (see picture).

I'd like to trade it for a piece of free-machining steel that is 2" x 2" x 2.5".