The THERMASGARD® ALTF 1 surface contact sensors are electrical contact thermometers and are used to measure the surface temperatures of solids, having at least one contact area that is brought into contact with the surface to be measured. The ALTF 1 surface contact temperature sensor with connecting cable and passive output determines the temperature of a fluid flowing inside a pipe via the surface temperature. The ALTF 1 is a tube contact resistance thermometer with strap and axial sensing tube for measuring the temperature on pipelines and tubes, or in heating sections for controlling heating systems.