
Mech. It's better than changing the batteries, but you have to unplug/replug often. I have two of these in two different locations and they each have the same problem. This does not coincide with power outages. I wouldn't recommend this for a place where you can't unplug/replug on a regular basis. (Like every week or bi-weekly.)

Soft Silicone AirPods Case Cover With Visible LED - Compatible With AirPod 2/1 Cases, Keychain Accessory Included - Ideal For Men, Women, Girls, And Boys - Light Pink
37 Review

Canon Nikon Sony Panasonic FujiFilm Olympus Pentax DSLR Camera Bag, Evecase Large Vintage Canvas Messenger SLR Shoulder Strap Case - Gray
45 Review

A Durable And Protective CaseSack For Bose QuietComfort And SoundLink Headphones
41 Review

Classic Camera Bag, Evecase Large Canvas Messenger SLR/DSLR Shoulder Case With Leather Trim, Tablet Compartment And Removable Insert For Mirrorless, Micro 4/3, Compact System, High Zoom Digital Camera
41 Review