Identifying Those Plastic Doodads

Q. One of my colleagues just got a new desktop computer, and I’ve noticed two little plastic doodads on the monitor cable. The installation booklet didn’t identify them, and she was about to pull them off, thinking they are like those Do Not Remove tags on new mattresses or maybe were moisture-absorbing packaging thingamajigs. But I suggested leaving them, on the theory that there must have been a reason for installing them. Was I right? And what do they do?

A. Yes, they’re there for a reason. They’re called ferrite chokes, and they’re designed to filter and reduce any radio-frequency interference that radiates from the system. They reduce the likelihood that interference will slow down the speed of your modem or local area network connection. If you don’t have them on your cable, it’s probably wise to pick up replacements. You can get them at any electronics store for about $5 a pair.