I got one of those. I don't know how accurate it is?...but, it is consistant. There's nothing electronic about it.

Mine ALWAYS read 7.0 everytime I put it into the soil? I suspected it wasn't working right?....so I ran a little test. I mixing some sweet pickle juice in with my regular 7.3 well water and then tested the soil. It read 6.5 to 6.7 ph!....perfect for soil!....and the plants turned out well, too.

I test 12 hours after watering.