This is a multifunction RJ45 network cable tester. It is the design of the network cable (RJ45) test, and telephone (RJ11). It is cheap and easy to use.

The ICON Digital Circuit Tester is a new test light that is available at Harbor Freight. Unlike an old-school device, this light provides a bright red (positive) or green (negative) LED numeric ...

Newer homes likely have a circuit breaker box that controls the power. You can use a circuit tester such as Klein Tools NCVT1P Voltage Tester to make sure you're in the clear.