I bought the pin for a normal board. Unfortunately, the pen does not write on the board, unless you press on so hot that the pen case is already almost broken. And then you get the few Cretaceous remains even by force from the board down. And when you contacted the seller so, you will still be making stupid that they would not deal properly with the stylus. But writing with a pen on a blackboard I manage just barely! Absolutely not recommended.
