I had this tester and used it everyday in my profession as an electrician. The old one I had broke after a drop off the ladder, but I had no doubts as to which one I was going to buy again. I like that it is a simple on/off tester. Simply hold down the power button to turn on and it will give you a loud "BEEP BEEP" and will silently flash red continuously to let you know it is on and working properly. All you have to do is place it near a live wire and it will give a constant "BEEEEP" an turn constant red to signify that the cable is live. After you are done using it simply hold down the power button again and it will turn off. It also has an auto off feature which will turn it off after a short period of time not using it. I have used other testers in the past but some are too complicated as they flash different colors to signify live currents and others you have to hold down the button while testing for a live wire. This is simple and I love fluke products as I think they are far superior to others when it comes to electrical testing.