The ST4 is a soil temperature probe based on a 10K thermistor (see specification for details).
The thermistor is housed in a stainless steel sheath of 6 mm nominal outside diameter, 120 mm long, connected to a 5 m or 10 m cable.
Thermistor type – 10 K
ST4-05 fitted with 5 m cable
ST4-10 fitted with 10 m cable