Column level indicators with temp. and MIN level electrical sensor MAX temp. electrical sensor in transparent polyamide-base technopolymer, screws, nuts and washers in polished zinc-plated steel, step-shaped packing rings for sealing on the tank wall and underhead O-ring of the screw in NBR synthetic rubber, float in technopolymer, bracket with watertight sensor in glass fibre reinforced polyamide-based technopolymer, adjustable connector and white lacquered aluminium plate.