The LX-4 Proton Mine is a proximity mine that is effective against both personnel and vehicles. Establishing a defensive perimeter around positions and facilities is its primary function. This follow up design, which was in the Imperial inventory at least after the Battle of Yavin corrected the inherent flaws of the LX-2. Unlike the LX-2 comlink mine that was originally thought to be "impregnable", the only means to disarm the LX-4 is to detonate it. In the previous design, transmitting a secret code would activate or deactivate the mines. On the planet of Calonica, a spot inspection revealed, alarmingly, that less then 10 percent of the 50,000 mines deployed around the capital contained explosives. A subsequent investigation revealed that Rebel spies had managed to obtain the classified code, and used it to pilfer the explosives from the LX-2s. The Rebels went so far as to rebury them to hide their brazen act.

    Buried generally around a half metre deep, the LX-4 employs two sensors to detect its targets. To detect vehicles, a gravity-sensitive sensor, which looks for magnetic disturbances created by large vehicles is fitted. For personnel, a thermal sensor geared towards body heat is also fitted. Either sensor can detonate the mine. The mine's charge is actually a refitted proton torpedo warhead.