For Christmas my wife bought me a beautiful Staedler mechanical draftsmans pencil that takes 2mm leads. She got an assortment of leads soft to hard. If you flip the lead around , you get a nice flat cylindrical end that works as intended to check Bhn of your alloy. If you lose track which lead you have in the pencil, it is nicely inscribed on the lead itself in easy to read white lettering. There is also a click type scale on the pencil body, simply twist the pocket clip to the proper lead hardness of the piece in the pencil, so you can recall when you come back to it. Really nice bit of kit.