The response of the R-21A sensor meets or exceeds the required time response (actual response of sensor is <6 seconds 0 to 90% O₂), and the quality and reliabilty are beyond standard requirements.

Recent major breakthroughs by Teledyne include the utilisation of a special plating on the cathode resulting in a 200 times greater resistance to the effects of CO₂. This increases the useful life of the sensor when used in exhaust emission testing.

Warranty: 12 months from date of invoice against defects in materials and workmanship.