With CrNi casing material 1.4571, brass screw-in nipple S.P. thread 1½" protection against dry operation 165°C – 30 K, 3 x 40 Amps. Application: CSN ® screw-in heaters with protection against dry operation are particularly suitable for calefaction of water (max. 100 °C/ max. 10 bar) in vessels or reservoirs with extremlely changing filling heights. By means of the built-in protection against dry operation the damage of the heating element due to too low a liquid level is prevented. Installation: The CSN ® screw-in heaters including protection against dry operation must be screwed-in horizontally in a bore hole with the S.P. internal thread 1½ ̋ such, that the probe of the protection against dry operation is situated at the highest position of the installed equipment