The O2NE+ is a simple to use and maintain ambient oxygen depletion monitor and sensor for use in laboratories which use inert gases and nitrogen.

Contact us today to find out why it is essential to monitor oxygen depletion levels in laboratories where gases like argon, helium and nitrogen are used.


The O2NE+ is an ambient oxygen depletion monitor comprising of a wall mounted main sensor unit and a repeater. It is ranged from 0 to 25% and has 2 low audio/visual alarms. The sensor has a very long life and calibration is only required every 12 months and can be achieved using certified air.

If you need to monitor both low and high levels of oxygen (for example, if you use enriched oxygen), the Safe-Ox+ oxygen depletion and enrichment monitor may be ideal for you.


Any laboratory using inert gases such as argon, xenon, nitrogen, krypton, radon or helium need to consider the O2NE+ oxygen depletioin monitor.  This unique monitor will help you comply with applicable legislation for your laboratory.

Inert gases are used in laboratories to conduct experiments, in cryogenics and as carrier gases, but  they do not support human breathing. Inert gases are odourless, colourless and tasteless, making them undetectable without an oxygen monitor.


The O2NE+ oxygen depletion monitor is usually situated in laboratories that are using multiple gases to ensure that oxygen levels do not deteriorate to an unsafe level. The unit is also sometimes used in the gas storage area where there is potential for a leak of helium or nitrogen.  The repeater is located at the entrance to the room.

O2 range

0.1 to 25%

Sensor accuracy

Better than ± 0.75% O2 over 5.0 to 25.0% O2

Response time (T90)

<60 seconds

Operating temperature

0 to +40 °C (+32 to +104 °F)

Temperature effect

0.2% of reading/°C or 0.1115% of reading/ °F

Atmospheric pressure range

811 to 1050 mbar absolute

Warm up time

10 seconds to normal operation, prior to calibration allow 2 hours to achieve full accuracy


Central unit = 175 x 105 x 75 mm, alarm repeater = 155 x 72 x 45 mm


Central unit = 600g, Alarm repeater = 150g

IP rating

IP65 for central unit and alarm repeater, unless the alarm repeater is quick connect then it is IP43

Sensor type

Electrochemical cell

Sensor life

Up to 7 years in air


4 digit LCD


2 x alarm visual indicators, 1 x system fault indicator, 1 x status indicator, common audible alarm

Alarm Sounder

Min 75dBA


One or two optional alarm relays with changeover contacts assigned to alarm 1, alarm 2 or system fault.
Contact rating 240 V AC or 30 V DC at up to 2 A, contacts are non-latching fail-safe


2 wire, 4 to 20 mA (max load 150 Ω)

Power supply options

210 to 250 V AC supply, 110 to 120 V AC supply, 9-24 V DC supply