MSA Ultima X/XE O2 sensor replacement. Replacing the internal sensor, not just the entire sensor

This video shows how the sensor can be dismantled to replace the internal oxygen sensor. The main reason to replace the internal sensor is to get extra life out of the sensor. The sensors only work for 2 years. Then they will give you erratic readings near the end of the life. This causes nuisance trips. The full sensor ordered from MSA may have been on the shelf for awhile before you received it. So replacing the internal sensor is the best cheapest option.