When you’re working on your car’s 12V wiring system, it helps to have a few special tools to get the job done. The Uber Tester is a 4-in-1 gadget that won’t remove door panel clips but does test for most wiring conundrums you might encounter. Plus, with its dual notification (buzzer and light), you’ll be able to use the tool when your stereo is blasting or when you’re contorted under the dash.

This 9V-powered handheld device will test the following scenarios with just three wires:

1. DC polarity — positive or negative voltage

2. Speaker polarity — “pop test”

3. Connectivity — wire loop back

4. Presence of voltage — fuse tester, constant or ignition switched power Installing a 12V accessory or stereo properly — that is, with the correct speaker polarity, switched power source, and constant voltage for the clock and preset memory — requires a tester such as this. Tracing wires in today’s vehicles is next to impossible with their nearly identical colors and tight wire looms. This gadget will help you find that needle in a haystack.