External wall resistance thermometer THERMASGARD~ ATF1 (internal sensor) and ATF2 (external sensor) with passive output. Housing made of impact-resistant plastic and with quick-release screws for measuring outdoor temperature, temperature in damp rooms, e.g. as a weather sensor, for mounting on external walls, in cold stores, greenhouses, halls, industry and agriculture. For outdoor use, mounting should preferably be north-facing or in a sheltered location. In case of direct solar radiation, a SS-01 sun protection must be used for the ATF1 and a SS-02 sun protection must be used for the ATF2.