Summary: This product does not work with the newest Wacom Cintiq 21ux. Although I believe that there is a newer one availible. It is black and Wacom lists it as model number KP400E2 under their accessories page for Cintiq 21ux.
Summary: I agree with other reviewers in that the pen lacks a certain substantiality. ie it feels like a toy and the control wheel has a chintzy feel to it. Also would it have killed them to include useful some documentation?