After some more cutting and prying—and a brief conversation about laser cutters—we bust through a second (this time metal) layer.

We're rewarded with the antenna and battery assembly. No graphite at the core of this Pencil.

This tiny 3.82 V, 0.329 Wh lithium-ion battery holds just 5% of the charge of an iPhone 6s battery.

For the sake of scorekeeping: Microsoft's Surface Pen has a user-replaceable AAAA battery. These are usually rated anywhere from 0.4 to 0.9 Wh.