It can be used to pick electronic locks and security devices, giving a bonus (+20%) to Lockpick.
In Fallout, the electronic lockpicks can be acquired by traveling to the Hub and entering the Thieves' Guild, where the Vault Dweller must accept and complete the quest to steal Daren Hightower's prized necklace. Subsequent to presenting the necklace to Loxley, the player character will receive the lockpicks as a token of their newly-acquired membership to the Guild. One may also find a secondary pair of electronic lockpicks in the upper-levels of the Cathedral. Yet another set of electronic lockpicks can be found in a locked locker on the fourth floor of the Mariposa Military Base near the Lieutenant.
In Fallout 2, the electronic lockpicks can be found in the basement of New Reno Arms, inside a well hidden fridge against the wall on the top left side of the basement map. The fridge also contains some pulse grenades, which conveniently also helps with getting into the underground storehouse of toxic caves.
Another set of these nice lockpicks may be found in a locker in the armory of the Oil Rig.