X01 140W USB-C Auto-Eject Full-Charge Separator

It sits between the charger and the phone and physically cuts the connection when the battery reaches full, which is a mechanical answer to a chemical problem: lithium cells age faster held at 100% than cycled below it, and an overnight charge holds them there for hours.

Rated to 140 W, so it passes through a laptop-class USB-C charger rather than throttling it to phone speeds — the usual failing of an inline gadget. Charging speed still depends on the charger, the cable and the device; this changes when charging stops, not how fast it goes.