I am doing a bunch of house work, and after getting a nasty shock a few years ago from a light switch that was supposedly turned off, I knew I needed one of these. Honestly for the price, it's a tool every house hold should have in their toolbox. It is very simple to use and can literally save your life. To use it, just turn it on and place is near the plug and it'll light up and beep if there's a current running through it. It has a million uses other than just making sure an outlet is working or shut off, I recently helped my dad figure out why one of his taillights would sometimes work and sometimes not, there was one wire that was causing it and this allowed us to find it with ease. It is very well made, because of the simplicity of this product and the lack of moving parts I can see it lasting over a decade with ease.