The EFP-06 is the default electrode for MT measurements.
The lifetime depends on the usage.
E.g. a replacement after 18-24 months is recommended.
When this type of electrode is already "much too old" you see high static offset and high noise in your time series.
A more detailed description can be found on Dr. Simon Andras's homepage.
DC .... 100 kHz
50 – 500 Ω (for normal soils)
a few mV
+5 to +50 °C
-0.1 mV/°C [-10° - +50° C]
the temperature drift of two electrodes in the current circle is much lower than -0.1 mV/°C because of the same electrical behaviour;
electrodes can be used at a wider outside temperature range if buried deep enough
appr. 0.7 kg
12 - 16 months; careful usage
length 117 mm, diameter 64 mm