ELockers use an electronic in-dash switch to control a set of magnets that causes a roller cams to engage pins that push into the side gear, locking the differential.
This is the prime advantage of an eLocker – it doesn’t require an outside source of power besides the standard 12-volt, and does not require an on-board air compressor to operate, as air lockers do.
This makes ELockers significantly more reliable and is why they are the preferred option for many 4WD owners.