Using ppO2 sensors, the O2NE+ is an ambient oxygen (O2) monitor designed to protect the lives of those working in an environment where inert gases including argon (Ar), helium (He), nitrogen (N2) and liquid nitrogen (LN2) are present.

When an inert gas leaks, it displaces the oxygen (O2) posing a risk to life. Oxygen (O2) should be maintained around normal atmospheric levels, 20.9%. Even a very small reduction in oxygen (O2) can cause effects on the human body such as headaches, confusion and shortness of breath.

Using an oxygen (O2) monitor, like the O2NE+ is the best way to protect people in these potentially hazardous environments. The O2NE+ also ensures adherence to exposure limit legislation such as OSHA and EH40.

O2NE+ Oxygen Monitor & Alarm Repeater
O2NE+ Central Unit - Dimensions
O2NE+ Alarm Repeater - Dimensions
O2NE+ Oxygen Monitor & Alarm Repeater
O2NE+ Central Unit - Dimensions
O2NE+ Alarm Repeater - Dimensions


The O2NE+ is a wall mounted oxygen depletion monitor, perfect to protect those in areas where an inert gas is piped, stored or used.

The system is quick to install and consists of a main sensor unit with digital display and a remote alarm repeater which is placed by the entrance to the room so you know if it is safe to enter or not.

Both parts of the system offer audible and visual alarms and the main unit continuously displays the ambient (O2) levels for the area.

The award winning O2NE+ boasts a very long-life sensor and requires very little servicing and maintenance.

Unlike most other oxygen (O2) sensors, the O2NE+ can be used in a helium (He) environment. Analox utilizes special technology to ensure that your unit is reliable and accurate even with helium present.

The O2NE+ key features include:

  • 1 x main sensor unit and 1 x remote repeater alarm
  • Long-life oxygen (O2) sensor
  • Oxygen (O2) Range: 0.1 to 25%
  • IP65 for central unit and alarm repeater
  • User changeable sensor
  • Calibration can be completed using ‘pure air’
  • Plug-in & Go – installed in minutes
  • Not cross sensitive to He

Optional Extras include:

  • 1 or 2 relays
  • 4-20mA output
  • Additional repeaters (for areas with multiple entrances)
  • Cable extension kits

Download our datasheet to see the full technical specification.

The O2NE+ oxygen depletion monitor is ideal for use in applications such as:

  • Cryogenics and cryopreservation
  • GC (Gas Chromatography) & Mass Spectrometry
  • Hospitals
  • Beer dispense & Nitro cocktail bars
  • CAS (Controlled Atmosphere Storage)
  • MAP (Modified Atmosphere Packaging) & Food storage
  • Commercial and Military diving (Heliox)
  • Restaurants
  • Pubs & Bars

The O2NE+ is designed to only monitor oxygen levels.

TOP TIP: An oxygen (O2) monitor will not protect you from carbon dioxide (CO2) exposure, this is a myth. If using carbon dioxide (CO2) you need a carbon dioxide (CO2) monitor. (Psst….Check out our Ax60+)

Analox can offer a wide range of support from helping you select the right features for your application, to service and maintenance advice as well as product training packages that can be tailored to your exact needs.

We also have a 24/7/365 emergency support helpline available to all customers.

Call us today to discuss your needs.

Standards such as OSHA, EH40 and the Confined Space Act advise on permissible limits for oxygen levels.

Analox are committed to helping you achieve your local and application specific legislation, please call us to discuss your requirements.


  • Replacement Oxygen (O2) Sensor
  • Flow Adaptor
  • Calibration Kit
  • Regulator Kit
Contact us