used TIF8800 Combustible Gas Detector - new batteries
I used this to test propane tanks at our church carnivals.

Item Combustible Gas Detector Kit Detects Combustible Gas and Other Chemicals Indicator Audible Standards UL Classifieds Only as to Intrinsic Safety in Class 1, Group A, B, C and D Hazardous Location, MSHA BatteryRechargeable NiCd Includes2 Batteries, Sensing Tip, 115V Battery Recharger, Carrying Case and Instructions

These detectors are MSHA approved and UL classified. The unique flexible 15" stainless probe allows you to access hard-to-reach places.
All feature automatic warm-up, are ideal for a tremendous range of uses, and are invaluable for safety in many applications.

Each unit includes its own rechargeable Ni-Cad batteries for years of use.
Detects dangerous explosive gases TIF8800 Electronic Combustible Gas Detectors
Used in almost any situation where combustible gasses, vapor or residues need to be found
Applications include: Gas lines and pipes, aids in identifying Heat Exchanger leaks and hazardous living/working environments (Note: NOT an effective Carbon Monoxide detector)
Instantaneous response
15" Flexible stainless steel probe
Automatic warm up
Ultimate sensitivity as low as 1 ppm (gasoline)
Adjustable sensitivity
Audible “Geiger counter” type signal
UL, CE and MSHA approved

Partial List of Detectable Compounds:

Compound Min. detectable concentration:
Acetylene 50 ppm
Iso-Butane (R600a) 500 ppm
Methane 500 ppm
Ethane (R170) 500 ppm
Propane (R290) 500 ppm
Ethylene 500 ppm
Hydrogen 500 ppm
Methyl Ether 500 ppm
Vinyl Chloride 5 ppm
Methyl Chloride 5 ppm
Hydrogen Sulfide 5 ppm
Acetone 50 ppm
Methanol 50 ppm
Ammonia (R717) 20 ppm
Gasoline 1 ppm
Chlorine 1 ppm

TIF8800 Combustible Gas Detector
Battery Charger 115V
Probe Length 15" (38cm)
Power Supply (Two) 2.4V Ni-Cad Batteries
Battery Life 4 Hours/Charge
Operating Temp 32º F to 125º F (0º C to 52º C)

pick-up only