*C**. W***. R****

* A – amperometric electrode on ceramic substrate
C- conductometric electrode on ceramic substrate
** 1 – 13 Sensor group reference number

W Working electrode material
1 – pure gold
2 – pure platinum
3 – pure silver
4 – Graphite

R – Reference electrode material
S – Silver
1 – Silver/Silver Chloride
2 – Silver covered by AgCl

(*) – Additional Technical specification
H – Heating of the sensor
T – Temperature sensing element