A USB data blocker is a small, inexpensive adapter that sits between a device and a charging cable or port. Internally, it only connects the power lines of the USB connection and leaves the data lines disconnected, so a phone or laptop plugged in through it can charge normally but cannot exchange data with whatever it is connected to.
Data blockers are mainly used as a precaution against juice jacking, the risk that a public charging port or unfamiliar cable might attempt to access data alongside power. Using one when charging from an unfamiliar port, such as in an airport or hotel, removes that concern without needing to carry a separate charger.
Because a data blocker also prevents any legitimate data transfer, it is best kept for occasional use with unfamiliar charging sources rather than as a permanent replacement for a normal cable at home or at work. See our USB security guide for related advice.
