Here an original CO2 sensor for an AP Diving Rebreather is offered.
A "CO2 Sensor User Instruction Manual" is available on the AP page. I recommend reading it. The sensor is connected between the controller and the temp stick.
In order to avoid incorrect measurements due to moisture, "CO2 Sensor Protectors" must be screwed on. Quote AP: "These are consumable items that need to be changed every 20-30 hours of diving." On apdiving.eu, a pack of 3 costs 28.62 EUR. The current Protector has done 2 diving hours. A new one is included.
Example to generate a CO2 alarm (at your own risk and not in the water!): Above the scrubber a sealing ring and then a spacer ring is correctly inserted. If the sealing ring is forgotten, much of the exhaled gas passes through the scrubber and absorbs the CO2. A small part of the gas will pass by the scrubber if the sealing ring has not been inserted and increase the CO2 content. This is enough for the CO2 sensor to report.
Current original price of the CO2 sensor on APDiving.eu: 1.031,63 EUR (as of 17.10.2022)
Available here used for 650 EUR
Shipping within the EU is free of charge. Return, warranty, guarantee and any liability are excluded.