@swordman Whether it works with the Onyx Boox device: Check the pen has EMR technology.
I'm using
this one.
@ottischwenk Last time I checked the Lamy was much better priced! Somewhere around 25€!
@swordman Take care to also look at the tip of the pen. The Staedler has a pointy tip with rubber feel, while the stock and the lamy have a rounded tip. It seems to be a point of personal preference. However, those preferences rather differ in our household. The thickness of the pen chosen is also rather different. The stock pen from Onyx is much thinner than both the Lamy and the Steadler Norris Digital.