The CPPM-4i features Sentinel Intelligent CO2 Enrichment™ (S.I.C.E.) which allows interfaced CO2 enrichment with Sentinel ICG series generators for unparalleled control (Patents Pending). Sentinel True Fuzzy Logic™ gives the most precise compressed CO2 regulator enrichment available. Large, pixelated LCD display makes user programming intuitive and simplified. Time Clock control provides greater user flexibility and control vs. older photocell models. Remote Sensor is 15 ft (5m) expandable up to 160 ft (50m) accommodating a wider range of growing environments. RoHS compliant construction for environmental friendliness.