What kind of circuit tester do I need?

[rgG]

Rick-o wrote:
I have several similar to this one. I used them out in the factories during demolition. If I tore out a wall with exposed romex, a quick touch with one of these would tell me if the wire was hot.

Works fine around the house too!

http://www.amazon.com/Voltage-Tester-Pro..._1?ie=UTF8&qid=1454033018&sr=8-1-spons&keywords=circuit+tester&psc=1


EDIT: ROMEX, spell check! NOT rolex!!

How would I actually use it, in the fixture, since I can't turn the fixture on? Would I touch the probe end to one of the wires, after I take the fixture off the wall? If so, which wire do I touch it to?