The ST120 socket tester with a GFCI test button from Fluke is a great introductory socket tester for home electricians and anyone wanting to quickly and easily test outlets. The bright, easy to read LEDs provide you with the information you need to easily recognize a miswired outlet. Plus, using the included table, you know how the outlet is miswired so you can repair it. The integrated GFCI test button gives you peace of mind by being able to individually check the GFCI trip function at your outlets, ensuring that they work as intended. The rugged yet compact design of the ST120 make it easy to carry with you to every job.