Electric resistance corrosion probes are used in different types for different applications of online corrosion monitoring. The corrosion rate of these probes can be measured online or transferred to the control system by using corrosion handheld or fixed data loggers or by corrosion transmitters.
The general type of ER probes element are as below:
* flush type 
* cylindrical
* spiral loop
* wire loop
* tube loop
ER probes can be provided by adapter in order to connect to data logger or transmitters. The length of probes is dependent on the mounting and monitoring position.