RH Concrete Moisture Meters The RH moisture meters from Accurate Weighing Scales can be used as Thermo-Hygrometers and for in-situ concrete moisture testing. Accurate Weighing Scales offers 3 handheld RH meters (listed below) dataloggers and wireless transmitters.The reusable, removable RH BluePeg Probes are designed for an accurate, fast and fail-proof measuring procedure following the ASTM standard F2170. After the initial investment, the only disposable part is the sleeve.