Apple Pencil

Apple Pencil is a line of wireless stylus pen accessories designed and developed by Apple Inc. for use with supported iPad tablets.
The first-generation Apple Pencil was announced alongside the first iPad Pro on September 9, 2015. It communicates wirelessly via Bluetooth and has a removable cap that conceals a Lightning connector used for charging. The Pencil is compatible with the first- and second-generation iPad Pro models, and all other iPads released in 2018 and later with a Lightning port.
The second-generation Apple Pencil was announced on October 30, 2018 alongside the third-generation iPad Pro. It uses a magnetic connector on the side of the tablet for charging rather than a Lightning connector, and includes touch-sensitive areas that can be tapped to perform actions within supported apps. It is compatible with all iPads with a USB-C port, including the 2020 iPad Air.
Specifications.
First generation.
The Apple Pencil has pressure sensitivity and angle detection, and it was designed for low latency to enable smooth marking on the screen. The Pencil and the user's fingers can be used simultaneously while rejecting input from the user's palm. One end of the device has a magnetically-fastened removable cap which covers a Lightning connector which is used for charging from an iPad's Lightning port. The initial charge lasts about 12 hours, but 15 seconds of charging provides sufficient power for 30 minutes of use. The Pencil ships with a female-to-female Lightning adapter which allows it to be used with charging cables. It is compatible with iPad 6th generation, 7th generation etc. models.
Apple has promoted the Pencil as being oriented towards creative work and productivity; during its unveiling, the Pencil's drawing capabilities were demonstrated using the mobile version of Adobe Photoshop, and its document-annotation capabilities were shown on several Microsoft Office apps.
The Apple Pencil uses an STMicroelectronics STM32L151UCY6 Ultra-low-power 32-bit RISC ARM-based Cortex-M3 MCU running at 32 MHz with 64 KB of flash memory, a Bosch Sensortech BMA280 3‐axis accelerometer and a Cambridge Silicon Radio (Qualcomm) CSR1012A05 Bluetooth Smart IC for its Bluetooth connection to the iPad. It is powered by a rechargeable 3.82 V, 0.329 Wh lithium-ion battery.
Second generation.
On October 30, 2018, Apple announced an updated Pencil alongside the third generation iPad Pro. It is similar in design and specifications to the first model, but without the detachable connector, and part of the stylus is flattened to inhibit rolling. It contains tap-sensitive zones on its sides that can be mapped to functions within apps. Custom laser engraving is available when purchased via the Apple Store online. 
Rather than a physical Lightning connector, the second-generation Pencil is paired and charged using a proprietary magnetic wireless charging connector on the tablet instead. As such, it is only supported by the third- and fourth-generation iPad Pro and the fourth-generation iPad Air. These iPads also have USB-C ports in lieu of Lightning, making them incompatible with the first-generation Pencil. iPads released in 2018 or later with a Lightning port, including the third-generation iPad Air, fifth-generation iPad Mini, and the 2019 and 2020 10.2-inch iPads, only support the first-generation Pencil.