THERMASGARD ® ALTF 1 Surface contact sensors are electric contact thermometers used for surface temperature measurement on solids, having at least one so-called contact area that is brought into contact with the surface to be measured. The surface contact temperature sensor ALTF-1 with connecting cable and passive output determines the temperature of a medium flowing inside a pipe (e.g. the water temperature) via the surface temperature. The ALTF 1 is a tube contact resistance thermometer including a strap and an axial sensor tube for temperature detection on piping and tubes (e.g. cold and hot water), or on heating trains for heating system control.