At first blush this pen looks like something a carpenter would use; it’s yellow so you can find it easy, has a ruler on it’s side, and if you look closely it even has a small bubble-level. However this pen comes with more than that.
Coming in silver, black, and bright yellow, the Monteverde One Touch Tool Stylus Pen also packs a small screwdriver bit hidden under the stylus tip. The ruler on the side of the pen is great for quick measurements on the field of small items. This notion of small also applies to the screwdriver bits. The dual-ended bit has both a flat and phillips head, but are small enough for glasses or electronics.
On the electronics front, the pen has a tablet stylus tip built into the cap covering the screwdriver. This cap is on the end opposite the paper-writing ink end. The stylus is a standard wide tip of conductive rubber, so the barrel of the pen is metal to conduct the capacitance of the writers hand.
The pen comes in two varieties: a cartridge-fed medium-nib fountain pen that uses standard international cartridges, or ballpoint. There was a complaint about it being difficult to change the cartridge, but one complaint doesn’t constitute a trend. If you want to carry a combination pen/stylus and have some of other tools just in case, this one might be for you.
If you like the pen version, you might also consider the 0.9mm mechanical pencil version.