It also comes with a USB-C charging cable, travel pouch, keychain holder, quick-start guide, and a manual.
Promising review: “I love this gadget. I fly a lot, and this works on the majority of wide-body planes I’ve taken over the past six months. Just plug into one of the three-prong outlets (or single outlet in economy), and you can connect any Bluetooth device. Doesn’t always connect on the first try, as I have multiple devices that my headphones are searching for, but if you turn off all other devices, it seems to connect right away. Once connected, it works for many hours. A few planes I’ve taken recently (Qatar Airways) have USB charge points so close to the headphone jack that you can even plug it in while it’s working and never lose the charge. Highly recommend for travelers.” —Joseph Sikorsky
Get it from Amazon for $34.99+ (available in four styles and two colors).