Item #: SCP-520
Laconic Containment Procedures: Keep the two switches in a lockbox and make sure they can't be switched on or off. Keep the two Persons of Interest (PoIs) in Foundation cells. If they cooperate, make the cells as comfortable as a hotel room, but don't let them phone home or tinker with anything electrical.
Laconic Description: SCP-520-1 and SCP-520-2 are a pair of knife switches, like the kind used in B-movie mad scientists' labs. Every time you flip one, it turns a random electrical device permanently on or off. The first one (SCP-520-1) affects a random device less than 10 meters away from it. You can program a maximum distance into the second one (SCP-520-2), and it will only affect a certain type of device, which it shows on a little screen. It picks a new type randomly after every 10 switchings. If there's nothing close enough to SCP-520-2 that it can affect, it either won't switch at all or will increase its own maximum distance. (Our researchers found that part out by accidentally crashing a jumbo jet.) The two switches came with a lot of construction notes.
Both the switches and the notes were made by Sylvia Lin (PoI-520-A) and Ester Pochazka (PoI-520-B). Ester is an old electrical engineer who learned to make anomalous electronics and was teaching the technique to her close friend Sylvia. SCP-520-1 was Ester's demonstration device. Sylvia tried to copy and improve it, and in the process built SCP-520-2. While testing it, though, she accidentally destroyed Ester's pacemaker. Ester survived, but with minor brain damage, and the Foundation isn't sure whether or not she knows how to make anomalous electronics anymore. She's very angry with Sylvia about the whole thing, especially since the Foundation wouldn't have caught them without that trip to the emergency room, and no longer wants to talk to Sylvia at all.
Additional Context: This article was rewritten in 2017 by the original author. The original SCP-520 was just a single switch like SCP-520-1 that could affect any electrical device on Earth.