Since 1910, General Tools has grown to become a recognized industry leader for specialty hand tools and instruments. The General Tools Multi-Function Thermo-Hygrometer with Pin/Pinless Moisture Meter can measure 1) ambient temperature, 2) relative humidity (RH), 3) absolute humidity (in mg/L or g/m3), 4) GPP (mixing ratio in grains per pound or g/kg), 5) relative moisture level using pinless sensor, 6) absolute moisture level using included pin-type probe, 7) dew point, 8) atmospheric pressure and 9) vapor pressure. It's ideal for water damage restoration contractors, facility maintenance professionals and HVAC system installers/technicians.
Stores/recalls 20 pairs of readings
Settable high and low alarms for RH, relative moisture level and absolute moisture level
Backlit LCD with 3-digit primary readout plus 4-digit secondary readout
Field calibratable humidity measurement
Min/max, data hold and 30-minute auto power off functions
Ambient temperature measurement range/accuracy: -20 to 167˚F
RH measurement range: 0 to 100%
RH measurement accuracy: ±2.5% from 11 to 90%RH; ±3%RH elsewhere
Absolute humidity range: 0.5 to 240mg/m3
GPP range: 0 to 999/GPP (0 to 160g/kg)
Relative/absolute moisture level range: 0 to 99.9%
Abrasion-Proof Display Lens,Automatic Calibration,Automatic Temperature Compensation,Backlit,Data Hold,Data Log/Record,Interchangeable Pins/Probes
Maximum Moisture Reading (%)
Maximum Sense Depth (in.)
Minimum moisture reading (%)
Number of Batteries Required
Product Weight (lb.)
Test Meter Type
Tools Product Type
Warranty / Certifications
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out of 8 reviews
100%recommend this product
Showing 1-8 of 8 reviews
Nov 9, 2021
Product was delivered used / clearly second hand, not new....
Product was delivered used / clearly second hand, not new. Am returning to store for refund at first opportunity.
Sep 15, 2020
Very satisfied with the performance however it’s difficult to read...
Very satisfied with the performance however it’s difficult to read the screen you have to look at it at a 45° angle. Planning on taking it back to have it replaced. Would buy again
Jan 8, 2020
This is a less expensive version of the meter I...
This is a less expensive version of the meter I had originally wanted. That said this meter performed very well. I am an RV Inspector so the non-invasive meter was essential. It works well on all interior surfaces of the unit and allows me to give my customers a better indication of condition.
Jan 2, 2019
Good all around water meter ...
Good all around water meter
Jun 19, 2018
This thing is a great tool, we kept having window...
This thing is a great tool, we kept having window sills and other trim crack and peel every year and really think the wood wasnt dry enough. Now we dont take any chances and check everything. Its a hot gizmo!
Dec 26, 2017
Meter works just as well as more expensive obes...
Meter works just as well as more expensive obes
2 found this review helpful
Oct 25, 2016
Great meter for the price. Has everything a $500 flir or extech meter would have. I bought 5 of these for my techs reason for 4 stars was because on 2 of the sets the prongs on the attachment were not pointed but instead hooked at the ends and when the first time i used it of course had to be on looped pile carpet and it hooks and pulls the loops coming back out of the carpet. Will have to file the tips down but shouldnt have to do so. Otherwise great product.
2 found this review helpful
Jan 7, 2015
General Tools & Instruments RHMG650
Super unit! Inexpensive and reliable.
Readings are dead on!
Used multiple readers on one job site this little unit was more accurate than the rest!
Going to purchase another 12 for the rest of my techs.
Recommended by a field adjuster and a home inspector.
For the price why not?