ISO roundline double acting cylinder, 25mm diameter, 50mm stroke

Generally the material chosen for a specific installation is governed by corrosion conditions to which the protection tube is exposed. In some instances, strength is a primary requirement while corrosion resistance is secondary.
For accuracy of the temperature measurement, the immersion length should be long enough to permit the entire temperature sensitive portion of the thermometer bulb, or the thermocouple element, to project into the temperature medium to be measured.