After a well handled issued that I had with Fluke, they got me straight with this Voltage Tester and I could not be more pleased.  I fully respect (spelled correctly?) electricity and will not mess with connections unless I know beyond any reasonable doubt that the power is off.  Over the years, I bought several of those really cheap testers each of us has and they worked o.k.,  until this past year.  I put the red and black to the line and it said it was not hot (electrical talk).  But when I unwound a wire nut and started to unwind the two wires.  ZAP!!  That jody was hot.  It almost lit me up.  With several electrical jobs  waiting for my attention, I put my faith in the Fluke iAC-A1-II and they gained a new customer.  It worked well and without any problems.  I can even open it, now.  When it comes time for different type testers and so forth I will be checking out Fluke.