Nagura's from mailman and a gift???

[Gasman]

I finally got my Nagura's and because I waited so long for my order, as the owner of JNS was on holiday vacation then was having personal problems at home, he sent this yellowish brown stone for free. No info with it at all so I don't know what it is. And being new to stones I cant even guess. I'm still short a Tomo Nagura as I didn't know of this item. Guess I'll be ordering another at a later date.

So what is it?
I'll give the Nagura's a try this weekend if I get a chance. Like a kid in a candy store and don't know what to do!