I'm very happy with my Alphatek one. Does everything I want it to very easily. The reason I went with it was, I was doing a periodic Test and inspection in a branch of Edmundsons. They keep the Alphatek so I cheekily asked if I could have a "test drive". It was easy to use, light, the RCD triplock actually works! And half the price of the last tester I had,the Robin 1630 ( overpriced, heavy and rubbish Dlok). BTW I'm very impressed with the level of electrical knowledge on this forum.