1,real-time display air ppllution index; 2,the air tester ... calendar. 1,newest calendar desigen:display year, moth, day, time, week;2,the air tester is test VOC, dust bacteria ... , stink,weat, etc;3,real-time display air pollution index air pollution index:0-250 0 ... , mainly tolunene, xylene etc(home decoration,volatile gas from painting), harmful gas is mainly test ammonia, sulfide.