The Comboinstruments Soil pH/ Humidity Meter works with all substrates. You can measure the coconut fiber, the stonewool, the perlite, the vermiculite, soil, and even clay pebbles.
The range of pH measurement: 3 ÷ 8
Humidity measurement range: 1 ÷ 8
Range of error 0.1 – 0.5
It does not require calibration
It does not require a battery
Maximum diameter: ø51mm