The box contents of the Lenovo ThinkPad Yoga digitizer (4X80F22110). More info and images below.
The pen is an thin and resembles a stylus more than it does a digitizer. The pen is a Wacom penabled device. There is a tip on the front, it has one button on the side, NO eraser, and the package does NOT include replacement tips. The package does NOT include replacement tips/nibs.
This type of pen will work with all Penabled tablets. So devices like Lenovo ThinkPad X series convertible tablets, many Fujitsu T series convertible tablets, anything Samsung "S-Pen" related, and of course the digitizer-supported Lenovo ThinkPad Yoga 12 (1st and 2nd gen).
I think the more comfortable one would be the Wacom Bamboo Feel, the nice one with eraser is the Lenovo X series 45N2630 digitizer, but the most functional is the Fujitsu LifeBook FPCPN28AP digitizer with two buttons.
From top: Wacom Pro Pen (NOT a Penabled digitizer), Fujitsu LifeBook Digitizer, Lenovo X series digitizer, and Lenovo ThinkPad Yoga digitizer.