Calibratable outdoor humidity/ temperature sensor HYGRASGARD® AFF/ AFTF (± 2.0 %) and AFF - 20/ AFTF - 20 (± 1.8 %) with plastic sinter filter (optional metal sinter filter) or AFF - 25/ AFTF - 25 (± 1.8 %) with pluggable metal sinter filter; housing made of impact-resistant plastic, with/ without optional display.