Originally released in 2012, the Surface Pen is a stylus designed for Microsoft's Surface line of devices including the Surface Pro, Surface Go, Surface Book, Surface Laptop, and Surface Studio. The Surface Pen has an active digitizer that boasts an impress degree of pressure sensitivity and palm rejection.
Surface Pen generations
The Surface Pen is currently in its fourth iteration. The following sections contain information on each generation.
Second Generation - On June 20, 2014, a new Surface Pen was launched alongside the Surface Pro 3. For this version, the "eraser" was moved to the body of the device, above the button used to right-click. A third button was placed on top of the pen, where the eraser was formerly located, that would automatically launch OneNote. The second generation of Surface Pen required batteries and included 256 levels of pressure sensitivity for improved accuracy of hand-drawn illustrations.
Third Generation - The Surface Pen was updated when the Surface Pro 4 went on the market. The additional side button added in the second generation was removed. The eraser was moved back to the top of the stylus, but the button functionality remained, and gained a few new features. Pressing the button once still brought up OneNote, but double-pressing took a screenshot, and holding the button activated Cortana. The pressure sensitivity of this pen went up to 1024 levels when it was used with the Surface Pro 4.
Fourth Generation - When the Surface Pro 2017 was released, the Surface Pen was updated yet again. This iteration was capable of 4096 levels of pressure sensitivity, 1024 levels of tilt sensitivity, and had the lowest latency of any stylus at the time. This pen was not included Surface devices, but was sold separately at an increased price.