Gas Detection For Life

Leading gas detector manufacturer


RKI banner
MSHA GX-2009

Smallest Four Gas Confined Space Monitor

MSHA GX-2009RKI is proud to offer the smallest and lightest 4-gas monitor with an MSHA rating, the MSHA GX-2009. MSHA (Mine Safety and Health Administration) certification allows this version of the GX-2009 to be used in underground mines, tunnels and excavations under MSHA jurisdiction. Weighing only 4.6 ounces, it fits in the palm of your hand.

The MSHA GX-2009 simultaneously monitors and displays % volume combustibles, oxygen, carbon monoxide, and hydrogen sulfide. Equipped with dual audible alarm ports and alarm LED’s on 3 sides of the instrument, so that alarm conditions are obvious from multiple perspectives especially in high noise environments. Other features include a water resistant and dustproof design with IP 67 rating, an impact resistant rubber over-mold body that is RFI resistant, and a large capacity data logging system included as standard.

  • Features
  • Specifications
  • Downloads
  • Parts


  • Simultaneous detection of 4 gases. CH4 & O2, PPM H2S & CO
  • Smallest / Lightest 4 gas monitor on the market
    2.7” H x 3” W x 1” D, 4.6 oz.
  • Dual audible alarm ports (95 db @ 30 cm)
  • 3 visual alarm LED’s
  • Vibration alarm
  • IP-67 Water resistant/dustproof design
  • Calibration and bump test lock out or reminder controls
  • Large capacity data logging standard
    • 8 alarm trends
    • Log time range of 10 to 300 hours
    • 100 calibration records stored
  • 20 hours of operation (NiMH batteries)
  • Large LCD display screen
  • Automatic backlighting at alarm
  • Impact resistant rubber over-mold body
  • Intrinsically safe, MSHA classified
  • 2 year warranty


  • Mining
  • Underground construction
  • Tunneling
  • Any application where an MSHA approved gas monitor is required
GX-2009 manhole

Other standard features are vibration alarm, auto-calibration, calibration and bump test lock out or reminder control, STEL / TWA readings, peak hold, auto backlighting at alarm on a large LCD display, and it even tells the time! All of these controls and features are operated through 2 simple glove friendly buttons. The NiMH battery set will operate for 20 hours and will fully charge in 3 hours.

A huge capacity data logging function is a standard feature on all GX-2009 instruments. The data logging software will store up to 100 calibration records and is Windows 8, 7, XP and Vista compatible.

To simplify maintenance and record keeping, the MSHA GX-2009 has the SDM-2009 single calibration station available. The SDM-2009 calibration station can operate as a stand-alone system or connect to a computer along with up to 10 other SDM-2009 units.
Gas Detected Combustible Gases (Methane as standard) Oxygen (O2) Hydrogen Sulfide (H2S) Carbon Monoxide (CO)
Sensor Catalytic combustion Galvanic cell Electrochemical cell
NC-6264B OS-BM2 ES-1827i ES-1821
Detection Range (Increments) 0 ~ 5% vol
(0.1% vol)
0 ~ 40.0% vol
(0.1% vol)
0 ~ 100.0 ppm (0.5 ppm) 0 ~ 500 ppm (1 ppm)
Accuracy Statement ± 5% of reading or ± 0.1% vol (whichever
is greater)
± 0.5% O2 ± 5% of reading or ± 2 ppm H2S (whichever is greater) ± 5% of reading or ± 5 ppm CO
(whichever is greater)
Sampling Method Diffusion sampling standard / hand aspirator or motorized pump optional
Display Digital LCD displays all four gases simultaneously, with auto backlight
Preset Alarms
(User Adjustable)
Overscale alarm
1st alarm 0.5% vol
2nd alarm 2.5% vol
Over alarm 5% vol
Low alarm 19.5%
High alarm 23.5%
Over alarm 40.0%
1st alarm 10 ppm
2nd alarm 30 ppm
TWA alarm 10 ppm
STEL alarm 15 ppm
Over alarm 100 ppm
1st alarm 25 ppm
2nd alarm 50 ppm
TWA alarm 25 ppm
STEL alarm 200 ppm
Over alarm 500 ppm
Types of Alarms Gas Alarm: 2 Increasing alarms, STEL, TWA, overscale alarm. O2 decreasing/increasing.
Trouble alarm: Sensor disconnection, low battery, circuit error, calibration range error
Display of Alarm Gas Alarm: Flashing LEDs, intermittent buzzer (95 db @ 30 cm), flashing gas value, vibration
Trouble alarm: Flashing LEDs, intermittent buzzer (95 db @ 30 cm), display of error message
Operating Temp. & Humidity -4°F to 122°F (-20°C ~ +50°C), 0 to 95% RH, non-condensing (splash resistant)
Response Time Within 30 seconds (T90)
Continuous Operation 20 hours after a 3 hour full charge (14 hours after 90 min charge)
Power Source Direct charging NiMH batteries, set of 2
Safety Design / Approvals MSHA classified
Size & Weight 2.7” H x 3” W x 1” D (Approx. 70 H x 75 W x 25 D mm), 4.6 ounces (approx. 130 g)
Case Material High impact over molded rubber. Dust and water resistant with IP-67 approval.
Controls Two buttons: POWER / MODE, AIR
Datalogging Standard with all instruments. Stores 8 alarm trend sessions where readings are recorded 30 minutes
before and after an alarm event. 3,600 data point capacity with a log time range of 10 to 300 hours
(based on programmable interval times); and stores up to 100 calibration records.
Required Accessories Battery charger
Standard Accessories Alligator clip 13-0116RK
NiMH batteries (set of 2) 49-1609RK
Charging station with 115/220 VAC power supply (also available without power supply, 49-2170RK) 49-2170RK-01
Product CD (includes datalogging software) 71-8002RK
Optional Accessories Belt Clip 13-0117RK
Padded carrying case for GX-2009 and accessories 20-0112RK-01
Charging station, 115/220 VAC powered for 2, 3, 4, or 5 instruments 49-2170RK-XX
Charging station with 12 VDC power supply and vehicle adapter plug 49-2171RK
12 VDC adapter with vehicle plug (does not include charger base) 49-2020RK
Hand aspirated sample draw with 10’ hose and probe (up to 40’ hose available) 81-1160RK
USB to IrDA downloading cable 47-5027RK
SDM-2009 single calibration station 81-SDM2009-01
Configurations • 4 gas, CH4 / O2 / H2S / CO • 3 gas, CH4 / O2 / H2S • 2 gas, CH4 / O2 • 1 gas, CH4
• 3 gas, CH4 / O2 / CO
Warranty Two years material and workmanship

GX-2009 MSHA parts
# Part Number Description
1 21-1880-MSHA Front case, GX-2009
2 07-6017RK-01 Gasket for GX-2009 case, one each
3 30-1054RK Vibration motor for the GX-2009
4 51-1119RK LCD module assembly with flat cable for GX-2009
5 57-2052-MSHA PCB main assembly, GX-2009
6 21-1881-MSHA Case, rear, GX-2009
7 10-1098RK-01 Screw with split lock and flat washers for alligator or belt clip, GX-2009, 1 each
8 10-1104RK Screw for case or sensor retainer, M2 x 10 mm, GX-2001 or GX-2009, pack of 100
9 33-1113RK-01 Metal mesh filter for buzzer hole, GX-2009, 1 each
10 07-6018RK Gasket for buzzer hole, GX-2009
11 24-5000RK Flexible printed circuit (FPC), GX-2009
12 49-1050RK Battery, silver oxide, SR 616, 1.55 volts, GX-2009
13 49-1609RK NiMH battery set with hardware for GX-2009, set of 2 batteries
14 13-0116RK Alligator clip, GX-2009
17 21-1883RK Sensor case with PCB assembly, GX-2009
18 07-6008RK O-ring gasket for sensor case, GX-2009, pack of 10
18 07-6008RK-01 O-ring gasket for sensor case, GX-2009, 1 each
19 OS-BM2 Sensor, Oxygen (O2) for GX-2001/GX-2003/GX-2009/GasWatch 2/OX-01
20 NC-6264B Sensor, LEL, for GX-2001/GX-2003/GX-2009 MSHA version
21 ES-1821 Sensor, Carbon Monoxide (CO) for GX-2001/GX-2003/GX-2009/GasWatch 2/CO-01
22 ES-1827i Sensor, Hydrogen Sulfide (H2S) for GX-2009
23 07-6019RK-01 Sensor chamber gasket,for sensor retainer,GX-2009, 1 each
24 21-1882RK Sensor retainer, GX-2009 (inner piece)
25 33-7114RK Filter disk, H2S scrubber, 5 pack, for combustible diffusion port, set of 5
26 33-7102RK Filter, charcoal, for CO sensor, pack of 5
26 33-7102RK-01 Filter, charcoal, for CO sensor, 1 each
27 07-6021RK Gasket, sensor retainer, pack of 10
27 07-6021RK-01 Gasket, sensor retainer, 1 each
28 33-0172RK Sensor Cover, water proof, sheet for 4 sensors, GX-2009, 1 each
29 21-1884RK Sensor cover, GX-2009 (outside piece)
30 10-1104RK-01 Screw for case or sensor retainer, M2 x 10 mm, GX-2001 or GX-2009, 1 each
31 13-0112RK Wrist strap, GX-2001/GX-2003
32 13-0117RK Belt clip, GX-2009

GX-2009 Video

This video will open in a new window. Also available on Youtube and CD (by request)
Specifications subject to change without notice. 

5 unit charger for GX-2009
Optional multi-charger available.


Remote Sample Drawing Pump

Remote Sample Drawing Pump RP-2009
A compact battery operated sample-drawing pump that attaches in line for remote, portable monitoring. .
RP-2009 Portable Sample Draw Pump


PC controlled Calibration Station

SM-2000 Calibration Station
A single module calibration station for the GX-2009 portable gas monitor that can calibrate, bump test, charge, and archive data.
SDM-2009 Calibration Station


Calibration Frequency

How often should I calibrate my GX-2009 gas monitor?

Calibration Frequency
What we generally recommend is that users develop a frequency of calibration that is tailored to their application and usage. Read more...

Service Tips

Filter Replacement & Battery Refresh

Service Tip
H2S scrubber filters, used to protect the CO and LEL sensors, should be replaced every six months....
Filter Replacement & Battery Refresh