Sentinel now offers 2 new CO2 controllers. The stand-alone CPPM-1 controls your CO2 levels with part-per-million accuracy and offers ease of use. The CHHC-1 controls all of your growing area conditions accurately & reliably. The CHHC-1 has all of the CO2 features of their stand-alone controller the CPPM-1. It also has the ability to control 3 other devices, a cooling device, a heating device and a humidity device. It offers separate day and night temperature and humidity settings, records the minimum and maximum temperature, humidity and CO2 levels. Both units feature a remote combination sensor that can be placed 15ft from the controller and can be easily calibrated by the user with a self calibration feature. For more information visit www.growgps.com