I've had these tips before and used them with my Wacom Intuos 4. They worked great! I recently reordered them in hopes of using them with a Surface Pro pen. Technically they fit in a pen. They're too long for the Surface Pro stylus, and for some reason the stylus doesn't even realize these tips are there, so the stylus lacks all functionality. TL; DR: Don't use these pen tips in Surface. About the pen.
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