Magnetic switches and hard-wearing keycaps
In a Hall Effect switch the key does not press metal contacts together: a sensor measures the position of a magnet under the key, so there are no contacts to wear out over time. PBT is a denser plastic than the more common ABS, and double-shot means the legends are moulded from a second layer of plastic rather than printed on top. On white keys that matters most: the letters stay put and the RGB light shines evenly between the keys.
