The Triplett Breaker Sniff-It
You won't need to use it very often, but when once you do, you'll wonder how you got along without the Triplett circuit breaker identifier. Most homeowners and apartment dwellers have no idea which of their circuit breakers control any particular light, outlet, or appliance (and few breaker panels are properly labeled). Here's why that matters: most electrical repairs are easy and safe to do by yourself. If you need to replace a five-dollar wall switch, there's really no need to pay an electrician a hundred bucks to come over to do it for you. As long as the power to the switch is really off, you are in no risk of electrocuting yourself.

In the "olden days" the way we'd find out which breaker serviced the wall switch in question was to have somebody upstairs watching the light, while we kept flipping the breakers one by one until the shout, "It's off!" was heard. Can't do that anymore. Our homes and offices are so chock-full of computers and electronic gear, killing the power randomly can lead to a lot of grief. That's where where the Sniff-It comes in handy. You just plug in the transmitter into the outlet (or lamp socket with a little adapter) and pass the detector wand over the breakers. It beeps when you're over the right one. Just flip it, and get to work. $53 at Jensen Tools.