That Is the famous/infamous PHIG. People's Hone of Indeterminate Grit. I got mine off ebay for something like 30 bucks shipped. And rougher than the one in your picture. If you get one, get It from the site gssixgun mentioned and save yourself a few hour's lapping time. They're hard as hell, and mine came with a natrual face on one side, wet saw kerf marks on the other.