Actually I think I could have just answered my own question (cheaper Co2 monitor).....
Desktop Carbon Dioxide (CO2), Temperature
and Humidity Indoor Air Quality Monitor
******
This 3-in-1 CO2 monitor (desktop type) is designed for fast and accurate measurement of CO2 level, air temperature and humidity. Features a triple LCD Display and 15° tilt angle for easy reading. Also features programmable alarms with real time clock and calendar. In addition, it has ABC (Automatic Baseline Calibration) and Manual Calibration option.
It can be set in 2 alarm limits: upper & lower limit. It has an audible & visual alarm to give warning when CO2 concentration exceeds the limit. Once CO2 level goes back to normal the alarm will automatically stop, but can be also be stop by pressing any key. The built-in Non-Dispersive InfraRed (NDIR) sensor provides long term stable monitoring.
Poor indoor air quality in rooms can lead to fatigue, lack of concentration and illness (Sick Building Syndrome) due to high CO2 concentration. IAQ monitoring and ventilation surveys of CO2 level & air ventilation become widely applied in public areas such as offices, classrooms, factories, hospitals, hotels.
Special Features
Maintenance free NDIR (non-dispersive infrared) CO2 sensor
Stable Non-Dispersive Infrared (NDIR) Sensor for CO2 detection
Simultaneous triple result complete with real time clock & calendar
15° tilt angle
Visible & Audible (80db) CO2 warning alarm when CO2 concentration exceeds the set limits
Large LCD display of CO2 level, temperature and humidity
ABC (automatic Baseline Calibration)
Manual CO2 calibration with calibration indicator
Indoor air quality level indication (Good, Normal, Poor)
Long time drift compensation
Max. & Min. CO2 value recall function
With level indicator, indicating if CO2 level is in "good", "normal", "poor" condition
With power adaptor output voltage indicator via LCD and LED light
Selectable °C and °F
With CE Marking, passed the standards and had been approved by European Directives for health & safety
Specifications
Measuring Range:
CO2: 0~9999ppm
Air Temp.: -10°C~60°C (14°F~140°F)
Air RH%: 0.1%RH~99.9%RH
Resolution:
CO2:1ppm
Air Temp.:0.1°C / 0.1°F
Air RH%:0.1%RH
Accuracy:
CO2:50ppm ±5% of reading
Air Temp.:±0.6°C, ±0.9°F
Air RH%: ±5%RH (at 25°C, 10~90% RH)
*******±7%RH (at 25°C, <10% & >90% RH)
Response:
CO2:<2 min (90% step change)
Air Temp.: <2 min (90% step change)
Air RH%: <10 min (90% step change)
Air Quality Level (CO2 Concentration):
Good: <700ppm (programmable by user)
Normal: 700 ~ 1000ppm (programmable by user)
Poor: >"Normal"
Operating Condition: -10~50°C, 5~80%RH (Be sure to avoid condense)
Storage Condition: -20~60°C, 5~90%RH (Be sure to avoid condense)
Alarm: >1000ppm (programmable by user)
Max/Min function
LCD & Green LED Display
Power Supply: Power adaptor (5V/0.5A output)
Set Includes
1 x CO2 Desktop Monitor
Power adaptor (5V/0.5A output)
1 x Instruction Manual
Standard White Packaging Box
I'll keep my fingers crossed you come back with the Genius Theory 
- STELTHY 
