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A pin and pinless moisture meter — for walls, not for comfort

General Tools RHMG650

A nine-function instrument combining a thermo-hygrometer with a pin and pinless moisture meter, recalling twenty reading pairs.

General Tools RHMG650 9-in-1 thermo-hygrometer and moisture meter with backlit LCD

General Tools RHMG650

A nine-function instrument combining a thermo-hygrometer with a pin and pinless moisture meter, recalling twenty reading pairs.

Measurements
9, including humidity, dew point and vapor pressure
Moisture meter
Pin and pinless
Temperature range
−20 to 167 °F
Memory
Recalls 20 reading pairs
Display
Large backlit LCD
Accuracy
Not stated by the maker
Refresh rate
Not stated by the maker
Calibration
Not stated by the maker
Amazon reference
B00I140G2E
EAN
0681035016084
  • The only instrument on this shelf with a pin and pinless moisture meter, which reads moisture inside timber and plaster rather than in the air
  • Publishes dew point and vapor pressure, which only one other instrument here does
  • Two bullets: no accuracy, no humidity range, no refresh rate, no calibration statement

Best for: Building and restoration work, where moisture in a material matters more than comfort in a room

≈ $220
Check price on Amazon

Specifications

Measurements
9, including humidity, dew point and vapor pressure
Moisture meter
Pin and pinless
Temperature range
−20 to 167 °F
Memory
Recalls 20 reading pairs
Display
Large backlit LCD
Accuracy
Not stated by the maker
Refresh rate
Not stated by the maker
Calibration
Not stated by the maker
Amazon reference
B00I140G2E
EAN
0681035016084

What the maker puts in writing

  • 9 measurements, including humidity, dew point and vapor pressure
  • Pin and pinless moisture meter
  • −20 to 167 °F · recalls 20 reading pairs
  • Large backlit LCD

That is the whole listing. Two bullets, on the most expensive instrument on this shelf.

A different instrument on the same shelf

Seven of the nine devices here answer “is this room comfortable”. This one answers “is this wall wet”, and it is the only one that can.

The pin probe goes into the material; the pinless pad reads through a surface without marking it. Neither has anything to do with the air, and that is the point.

Where the listing fails it

On a measuring instrument, the accuracy is the specification. Four devices on this shelf publish one, and the most expensive of those four costs under twenty-two dollars.

This page cannot tell you how close the readings are, because the maker has not said.

Availability

Read on the day this page was built: $220 at the American Amazon shop.

Read from Keepa on the day this page was last revised; stock and price both move without notice.

Prices quoted in this text were read on 2026-10-04. The live price is at the top of the page.

The questions that keep coming up

Why would I want a pin moisture meter?

Because air humidity and material moisture are different problems. A pin meter reads the water inside timber, plaster or screed; a hygrometer reads the air. If you are chasing damp, drying a floor or checking firewood, that is the measurement you need, and nothing else on this shelf takes it.

How accurate is it?

The listing does not say, and that is remarkable on an instrument at this price. Four devices on this shelf publish tolerances and all four cost under twenty-two dollars. For a professional instrument, ask the seller for the datasheet before buying.

Will it work as a room thermometer?

It will display temperature and humidity. What it will not do is sit on a shelf showing them: there is no mount, no comfort indicator and no logging, all of which the household devices here offer.

More thermo-hygrometers

  • LittleGood 6-inch analog wall thermometer and hygrometer with white ABS case

    LittleGood HMTMHY-WT

    A 5.9-inch analog dial reading −30 to +50 °C (122 °F) and 10 to 100 per cent humidity, with a calibration screw on the back.

    Type
    Analog — no batteries
    Dial
    5.9 in / 15 cm diameter, large black numerals
    Temperature
    −30 to +50 °C (122 °F) / −20 to +120 °F, accuracy ±2 °C (36 °F) / ±3.6 °F
    Humidity
    10 to 100%, accuracy ±5%
    Calibration
    Adjustment screw on the back for the temperature
    Scales
    Both Fahrenheit and Celsius, color-coded dial
    Mounting
    Supplied stand, or wall mounting hole
    Case
    White ABS
    Refresh rate
    Not applicable — analog
    Amazon reference
    B09P37W7CY
    EAN
    0613965381178
    • The only analog instrument on this shelf that publishes both tolerances and includes a calibration screw
    • A 5.9-inch dial with large numerals, readable across a room, which no digital display here matches for size
    • ±2 °C (36 °F) is the loosest temperature tolerance published on this shelf

    Best for: A wall in a garage, porch or workshop, read from across the room, with no battery to change

    ≈ $14
    Check price on Amazon
  • Reed 8706 digital psychrometer and thermo-hygrometer with dual-line LCD

    Reed 8706

    A digital psychrometer displaying humidity, temperature and dew point or wet bulb together, with Max/Min/Avg and data hold.

    Displays
    %RH, temperature and dew point or wet bulb, simultaneously
    Readings
    Max, Min and Average
    Data hold
    Yes
    External probe
    Optional 87P6, for contact and differential temperature
    Units
    User-selectable °F / °C
    Power
    Batteries; low-battery indicator and auto shut-off
    Stated uses
    Environmental studies, food distribution, HVAC/R installation, greenhouses, industrial spaces, saunas, humidors, museums, lab monitoring
    Accuracy
    Not stated by the maker
    Range
    Not stated by the maker
    Amazon reference
    B0C6BJ612L
    EAN
    0800837000057
    • Shows humidity, temperature and dew point or wet bulb on screen at the same time — the only instrument on this shelf that does
    • An optional external probe for contact and differential temperature, which no other device here offers
    • No accuracy and no measurement range published anywhere in the listing

    Best for: HVAC work, a humidor, a museum case or a greenhouse, where dew point matters and the reading has to be recorded by hand

    ≈ $125
    Check price on Amazon
  • TempPro TempAir digital hygrometer and indoor thermometer with wide LCD display

    TempPro TP53

    A digital hygrometer accurate to ±2 °F with all-time and 24-hour high and low records and a touch-activated backlight.

    Temperature accuracy
    ±2.0 °F (±1.1 °C)
    Humidity accuracy
    ±2 to 3% RH
    Refresh
    Every 10 seconds
    Records
    All-time and 24-hour high and low, stored and displayed
    Comfort indicator
    Yes
    Backlight
    Touch-activated, via a button below the display
    Mounting
    Holder, hanging hole and magnetic back
    Range
    Not stated by the maker
    Logging
    High and low only — no curve or export
    Amazon reference
    B079N98K93
    EAN
    6971604200285
    • The only device on this shelf that keeps high and low records — both 24-hour and all-time — without needing an app
    • Publishes both tolerances, with the humidity figure tighter than two cheaper devices here
    • A ten-second refresh, the slowest of the three published on this shelf

    Best for: A nursery, cellar or greenhouse where the overnight low matters more than the live reading

    ≈ $16
    Check price on Amazon

Elsewhere in the spares drawer

  • ALITOVE universal 5V 1A power adapter with 8 interchangeable connector tips

    ALITOVE Universal 5V 1A Power Adapter (8-Tip)

    A generic 5V DC power adapter rated up to 1A (5W), sold with 8 interchangeable connector tips to match different barrel-plug sizes. This is a universal-fit accessory, not one built for a specific reviewed model — the voltage, current and polarity printed on your original adapter's label are what actually determine a safe match, not the appliance's brand or size. Confirmed with a single live offer on Amazon.de; we did not find a listing on the other three markets we checked.

    Output
    5V DC, up to 1A (5W)
    Connector
    8 interchangeable barrel-plug tips included
    Fit type
    Generic / universal — voltage and polarity match required
    Input
    100-240V AC, per the listing
    • Confirmed with a live offer on Amazon.de
    • 8 interchangeable tips cover several common barrel-plug sizes without buying multiple adapters
    • 5V/1A only — not a fit for any appliance on this site needing a higher voltage or current, which must be checked on the original adapter's label first

    Best for: A small, low-power device — most commonly an air-quality monitor or a small humidifier accessory on this site — that specifically takes 5V/1A and whose original adapter has failed, confirmed against the original's printed label first.

    Search Amazon for this model
  • Bosch original replacement filter 2-pack for the Dry series dehumidifiers

    Bosch Original Filter for Dry Series (2-Pack)

    Bosch's own replacement filter for its Dry series dehumidifiers, covering the 1000, 2000 and 4000 models — including the Dry 4000 reviewed on this site. Confirmed with a live offer on Amazon.de; we found the same listing on Amazon.fr but did not verify a live offer there at the time of checking.

    Compatible models
    Bosch Dry 1000, Dry 2000, Dry 4000
    Pack size
    2 filters
    Source
    Official Bosch part
    EAN
    4069143068687
    • Official Bosch part, matching the model reviewed on this site exactly
    • Confirmed with a live offer and multiple sellers (5) on Amazon.de
    • We found a matching listing on Amazon.fr but did not verify a live offer there at the time of checking

    Best for: Bosch Dry 4000 owners who want the manufacturer's own filter rather than a third-party alternative.

    Check price on Amazon
  • ChiliTec ST35 plug-in outlet thermostat with analog rotary dial

    ChiliTec ST35

    ChiliTec's ST35 is an analog plug-in thermostat rated 230 V, max. 16 A / 3,500 W, switching a connected heater or fan on and off around a 5–30 °C (41 to 86 °F) setpoint in 1 °C steps. A slide switch sets heating or cooling mode, and the sensor is built into the plug itself rather than an external probe.

    Max. load
    230 V, 16 A, max. 3,500 W — stated by ChiliTec
    Temperature range
    +5 °C (41 °F) to +30 °C (86 °F), adjustable in 1 °C steps
    Switching behavior
    ±1 °C (34 °F) threshold, 10-second measurement interval, with a delayed reading ChiliTec says is meant to stop the relay tripping on a passing draft
    Mode switch
    Slide switch between heating and cooling; the connected device is driven in whichever mode is selected
    Sensor
    Internal — reads the air at the plug, not a remote probe
    Protection rating
    IP20, indoor use only
    Dimensions / weight
    H 128 × W 68 × D 39 mm (5.04 × 2.68 × 1.54 in) as plugged in; 190 g
    Amazon reference
    B01MZFKWS5 (EAN 4250416312457) — live offer confirmed on DE/FR/IT/ES; listed with no live offer on GB, no ASIN found on US, at check time
    • 3,500 W / 16 A rating is published by name, not left to be inferred from the plug
    • A heating/cooling slide switch means the same unit can drive a fan or a cooling device, not only a heater
    • Internal sensor only — it reads the air right at the socket, which runs warmer than the middle of the room once a heater has been on for a while

    Best for: Adding a numeric-ish setpoint to a heater or fan that only has a low/medium/high dial, in a dry room where the socket sits close to where you actually want the temperature held.

    Search Amazon for this model

All thermo-hygrometers