AirPods

The AirPods are a line of wireless Bluetooth earphones designed and marketed by Apple.

Models

 * AirPods (1st generation) - resemble a wireless version of Apple's EarPods, which are included with iPhones and iPods. They contain Apple W1 processors, which controls the Bluetooth 4.2 connection and optimizes battery use. The charging case accepts power through a Lightning port at the bottom of the case.
 * AirPods (2nd generation) - often called AirPods 2, feature the same exterior design, but contain more efficient Apple H1 processors, which adds "Hey Siri" functionality, faster device connection, lower latency, and 50% more talk time. Available with a new wireless charging case, which is distinguishable by a small LED indicator on the front and is backwards compatible with the 1st generation.
 * AirPods (3rd generation) - feature the same Apple H1 chip, but with a new contoured exterior design, improved acoustic system, and support for Spatial audio. A force sensor on the shortened stem provides control of music and phone calls.
 * AirPods Pro - contain an Apple H1 processor with new, water resistance, and interchangeable silicone tips featured in 3 sizes. Introduced in October 2019, it also includes a redesigned wireless charging case.
 * AirPods Max - a larger over-ear version introduced in December 2020. An Apple H1 processor is included in each ear cup. A Digital Crown, like the one from Apple Watches, is used for volume, playback, and Siri control.

Features
The in-ear AirPods have an ambient light sensor near the ear tip to sense when they're in an ear to start/stop playing sound. The in-ear models are provided with charging cases, which contain their own batteries for up to 24 hours of listening time or up to 18 hours of talk time over multiple chargings.

Articles

 * Earbuds to AirPods – A Timeline of Apple’s Iconic White Headgear by Andy Chen at LonelyBrand (2021-07-14)