PALIDA AIR MONITORING systems, is available in 2 version: 1. PALIDA AIR MONITOR "SINGLE": complete stand alone AIR-CLIMATE-MONITOR 2. PALIDA AIR MONITOR " MASTER" and PALIDA AIR MONITOR "SLAVE" for complete AIR MONITORING on multiple locations, with multiple sensors data centrally stored and maintained. . The PALIDA AIR MONITORING,measures: - temperature - humidity - oxygen O2 - carbonmonoxyde CO - carbondioxyde CO2 - ozone O3 - light - day- & night cycles - power status of the AIR-monitores - homoginity of the AIR-climate . The PALIDA AIR MONITOR "SINGLE" and "SLAVE" version store monitor the data in "continious loop" ( every second,minute,hour ) and are powered by re-chargable batteries. They work wire-less Maximum distance between PALIDA AIR MONITOR "MASTER" and PALIDA AIR MONITOR "SLAVE" is 250 meter. Maximum 24 SLAVE's per single MASTER . All data is stored on a SD-card,which can be read by the software,provided by PALIDA or any regular software. . For further questions and remarks,please contact us. Best quality, most flexible,most proffesional, most complete, best price !