Portable gas monitors to detect gases in the surrounding atmosphere. They measure concentrations of toxic gases and oxygen in the atmosphere and issue an alarm when gas concentrations reach preset levels. The alarms are indicated by flashing lamp, intermittent audible buzzer, flashing gas concentration readout and vibration.

| Specifications | |
| Gas alarm: | STEL Alarm, TWA Alarm, Over |
| Alarm volume: | 80 db |
| Humidity: | 0 ... 95 % RH (OX-04G: 10 ... 90 % RH) |
| Detection principle: | Electrochemical type (OX-04G: galvanic cell type) |
| Dimensions (W x D x H): | 54 x 24 x 67 mm |
| Weight: | 93 g |
| Power supply: | 2 x AAA alkaline batteries, or 2 x AAA rechargeble batteries (Ni-MH) |
| Protection class: | IP 66/67 |
| Warranty (sensor): | 3 years (OX-04G: 1 year) |