I have been using this tester (several replacements for lost and broken testers but always this one) for ten years. I'm an IBEW Electrician, I mainly do Commercial Construction and TI (Tenant Improvement) so I need something accurate and reliable. Although I always recommend that you hire a professional, this is a good tool for checking tension. This is in no way a substitute for a digital meter, it is the first step in checking for the absence of voltage.