I bought the specific model DDS528, which does not zero and does not have 2 values displayed. So for these two options that it does not have, it is not worth buying for me.

My review is about the DDS6619.

Easy installation, good construction, not excellent but seems satisfactory, the screws tighten and hold the cables perfectly. Installation on the panel and indications of the consumption of the entire installation.

In operation, it seems to be particularly accurate, with a multimeter I saw minimal deviation. On the initial screen, it shows the kwh consumed (two values, one of which zeroes) and by pressing the button/arrow, you can see voltage, current intensity, instantaneous power (I bought it mainly to see the approximate consumption of each of my devices during operation, and it does so with excellent accuracy), frequency, and power factor!

The only negative thing for me is that it does not stay on the screen you choose (I would always like to see the instantaneous power consumption) and it returns to the initial screen with the kwh after about 20 seconds.

You can get it at half the price from a foreign website (China) but you will have to wait for 1-1.5 months.

I would prefer the WDS688 model with Wi-Fi and recording and control from the mobile phone, but for now, I couldn't find it anywhere in Greece and its price is over 20€ abroad, considering the prices in Greece.

For someone who wants to see the above at a reasonable price, I highly recommend it.