Choose the Standard Four-Gas Diffusion Configuration
This portable monitor’s standard online combination is combustible gas on a LEL scale, oxygen, carbon monoxide and hydrogen sulfide. It uses diffusion sampling. Compare that combination with the gases required by the task before choosing an alternative sensor package: the extended gas table below lists custom options, not all gases installed in one standard unit.
Listed Purchase Options
| Option | SKU |
|---|---|
| LEL + O2 + CO + H2S | GAS-TU7K-01 |
This online option is the listed LEL + O2 + CO + H2S combination. The additional sensor choices below are not extra channels included with this SKU.
Questions That Help You Choose
Are these the four channels I need?
The standard configuration is LEL + O2 + CO + H2S. Another sensor combination is a separate configuration question, not an extra standard online channel.
Does diffusion fit the sampling plan?
This model has no internal pump. Compare the pump model when active sampling is needed.
What should a custom request specify?
List the required gases and ranges together. Custom sensor choices are not the same as selecting a listed standard unit.
For the buying comparison, read portable multi-gas selection guide and four-gas vs. five-gas comparison.
Compare internal-pump four-gas option.
Compare Standard and Pump-Assisted Purchase Options
The BH-4A four-gas monitor lists standard and pump-assisted variants as separate choices. This page lists the diffusion configuration. Compare those purchase options when a pump is part of the task, while keeping the required O2, H2S, CO and LEL channels as the basis for the comparison.
The portable 4 gas monitor simultaneously checks combustible gas (LEL), oxygen (O2), carbon monoxide (CO), and hydrogen sulfide (H2S) through diffusion sampling. The four readings appear together on the LCD, making the instrument suitable for field and facility checks where these common atmospheric hazards must be monitored.
Standard Configuration and Custom Gas Options
The standard online configuration is LEL + O2 + CO + H2S. The Gas Monitor can also be customized with the additional supported gas sensors listed below. Custom configurations are not standard online variants; contact us before ordering to confirm the required gas combination, measuring range, sensor availability, and quotation.
| Gas | Range | Accuracy | Minimum Reading | Sensor Response Limit |
|---|---|---|---|---|
| Combustible Gas (LEL) | 0-100% LEL | ≤±5% F.S. | 1% LEL | ≤15 s |
| Oxygen (O2) | 0-30% vol | ≤±5% F.S. | 0.1% vol | ≤20 s |
| Carbon Monoxide (CO) | 0-1000 ppm | ≤±5% F.S. | 1 ppm | ≤25 s |
| Hydrogen Sulfide (H2S) | 0-100 ppm | ≤±5% F.S. | 1 ppm | ≤30 s |
| Sulfur Dioxide (SO2) | 0-100 ppm | ≤±5% F.S. | 0.1 ppm | ≤30 s |
| Nitric Oxide (NO) | 0-250 ppm | ≤±5% F.S. | 1 ppm | ≤60 s |
| Nitrogen Dioxide (NO2) | 0-20 ppm | ≤±5% F.S. | 0.1 ppm | ≤25 s |
| Chlorine (Cl2) | 0-20 ppm | ≤±5% F.S. | 0.1 ppm | ≤30 s |
| Ammonia (NH3) | 0-100 ppm | ≤±5% F.S. | 1 ppm | ≤50 s |
| Hydrogen (H2) | 0-1000 ppm | ≤±5% F.S. | 1 ppm | ≤60 s |
| Hydrogen Cyanide (HCN) | 0-50 ppm | ≤±5% F.S. | 0.1 ppm | ≤200 s |
| Hydrogen Chloride (HCl) | 0-30 ppm | ≤±5% F.S. | 0.1 ppm | ≤60 s |
| Phosphine (PH3) | 0-1000 ppm | ≤±5% F.S. | 0.1/1 ppm | ≤25 s |
| Ozone (O3) | 0-20 ppm | ≤±5% F.S. | 0.1 ppm | ≤50 s |
Alarm and Display Features
- Audible, visual, and vibration alarms with sound pressure above 90 dB
- LCD shows gas concentration, gas type, unit, battery level, and time
- Chinese and English interface options
- ppm and mg/m³ unit switching where applicable
- Diffusion sampling without an internal pump
- Integrated back clip for portable use
Technical Specifications
| Standard gas configuration | LEL + O2 + CO + H2S |
|---|---|
| Custom gas options | Available by inquiry; see the supported gas table above |
| Sampling method | Diffusion |
| Linear accuracy | ≤±5% F.S. |
| General response time | <10 s |
| Alarm modes | Audible, visual, and vibration |
| Alarm sound pressure | >90 dB |
| Display | LCD |
| Power | 3.7 V rechargeable lithium-ion battery |
| Standby time | At least 30 days |
| Use time | At least 24 hours |
| Operating temperature | -35 to 65 °C |
| Operating humidity | 10-95% RH, non-condensing |
| Dimensions | 146 x 71 x 42 mm (H x W x D) |
| Approximate weight | 0.25 kg |
| Housing / ingress protection | ABS / IP66 |
| Explosion protection | Ex ib IIC T4 Gb |
Use Notes
Because the gas detector uses diffusion sampling, the surrounding atmosphere must reach the sensor openings. Alarm settings, calibration, bump testing, and operating checks should follow the supplied sensor documentation and the workplace safety procedure.
Free Shipping
Free shipping is available on all orders. Shipping methods and carriers may vary depending on the destination, order details, and available logistics options. Full Shipping Policy
Returns Policy
For returns and refunds, please review our full Refund Policy before placing an order. If you need help with an order, contact us before your order has shipped whenever possible. Full Returns Policy
When Will My Order Ship?
For Standard Shipping, we aim to pack and ship out your order within 4 business days. During special periods, such as heavy order processing or local inventory shortages that require deployment, please expect it to take an additional day or two for processing. We ship five days a week, Monday through Friday.
You will receive a shipment confirmation with tracking information via email when your order has shipped. Once you receive this email, we cannot change or cancel your order.
Can I Change The Shipping Address On My Order?
Please contact us immediately via email if you realize that you gave us the wrong shipping address — if it hasn't shipped yet, we might be able to correct it before it goes out the door.If your order ships to the address provided and is returned to us as undeliverable, then you are responsible for paying the cost of shipping again to resend it to you. If you decide you do not want your order reshipped, we'll refund you for the products less the original shipping charges, once your order returns to our warehouse. We'll reach out to you to coordinate your options before re-shipping.
If your order ships to an incorrect address provided at the time the order is placed and is not retrievable, we are not responsible and cannot offer reimbursement.
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Let customers speak for us
My first impression after opening and installing batteries was that this meter is very well built considering the price and manufacturer. I had read some reviews stating that it's amp measurements were not accurate below 5 amps, I haven't seen any issues in any measurements I've taken, even side by side with my fluke meters. I've successfully taken accurate amp, voltage and continuity measurements with this ETCR6920B, the display is nice and legible. I haven't tried storing data and making transfers to a PC yet, the soft case is good enough for storage on a shelf and the test leads are of good quality and rated for 1000v. There's nothing bad to say about this meter especially when you consider the price, it's a really great meter.
Works as described.
