| Model | GD400-4GAS | 
| Sampling Method | Pump suction & diffusion dual-use type | 
| Gas Type | CO, H2S, O2, LEL | 
| Principle | Catalytic combustion (LEL), Electrochemistry (CO, H2S, O2) | 
| Measuring Range | CO: 0-500/1000/2000ppm, H2S: 0-100/200/500ppm, O2: 0-25% VOL/0-30% VOL, EX/LEL: 0-100% LEL | 
| Resolution | CO: 1ppm, H2S: 0.1ppm, O2: 0.1% VOL, EX/LEL: 1% LEL | 
| Response Time | ≤30 seconds | 
| Precision | ≤±2%F.S except for special gases | 
| Language | Chinese/English (More languages can be customized) | 
| Automatically Test and Calibrate After Power-on
 | Including reset, maximum value (MAX), minimum value (MIN), STEL, TWA value | 
| Unit | PPM and mg/m3 can be switched and displayed by one key, and the concentration value is automatically converted by the system. | 
| Display | Monochrome graphics (160 x 96), screen can be automatically flipped. | 
| Backlight | The backlight time can be manually set and will be turned on automatically when an alarm is issued. | 
| Data Record | Can store 100,000 sets of data, the storage interval is adjustable from 5 to 3600 seconds, data can be exported, with a data cable | 
| Alarm | 95dB buzzer (@30cm), vibration alarm and flashing red LED and alarm status indication on the screen, alarm latched; diagnostic alarm and battery undervoltage alarm, pump block alarm; man down alarm, with early warning and optional real-time remote Bluetooth notification function | 
| Battery | 3.7V rechargeable lithium battery, battery capacity 2200mA | 
| Working Hours | More than 15 hours in continuous pumping mode | 
| Charger | Travel charger with DC interface, charging time ≥ 4 hours | 
| Explosion-proof Grade | Ⅱ 2G Ex ia Ⅱ CT4 Ga | 
| Certification (EU Regulations) | CE, ATEX (Standard: EN IEC 60079-0:2018, EN 60079-1:2014) | 
| Protection Grade | IP67 | 
| Working Temperature | -20℃~+50℃ | 
| Humidity | 0~90%RH (no condensation) | 
| Environmental Pressure | 86~106Kpa | 
| Size | 157*84.5*59.5mm (including the back clip/water trap filter) (length*width*height) | 
| Weight | 365g (including battery, belt clip and filter) | 
| Extension Probe | About 480mm (Total Length), About 300mm (Probe Head) | 
| Package Included | 1 piece gas detector, 1 piece 12V/1A DC power adapter, 1 piece USB cable, 1 piece user manual, 1 piece warranty card, 1 piece filter, 1 piece aluminum suitcase |