Check the listing for details. CO2 Controller / Monitor. Color: White, Condition: New. Listed at 85.00 USD. Up for sale is a "C.A.P PPM-4 CO2 Monitor Controller Carbon Dioxide Hydroponics PPM4 CAP Sensor." Condition is new sealed. Please refer to photos for more details. The **CAP PPM-4** is the newest addition to C.A.P.?s CO2 metering lineup, offering indoor gardeners the most economic and simplest method of monitoring and controlling CO2 dispersal throughout their growing area. The simplicity of this unit will make it attractive to both the beginning hobbyist and the seasoned grower alike.Operating the **CAP PPM-4** is as easy as mounting the meter to the wall, plugging the meter into the power interface and plugging in your CO2 generator or regulator. The PPM-4 utilizes a highly visible and intuitive LED indicator display to let you know generalized CO2 levels at a glance from across the room. PPM-4 also features an easy to use calibration function. New **CAP PPM-4** CO2 Controller! Monitor and control CO2 dispersal throughout the growing area Highly visible and intuitive LED indicator display to let you know generalized CO2 levels at a glance from across the room Easy to use calibration function. 0-900 PPM 901-1450 PPM 1451+ PPM 10 Amps @ 120 Volts Product Condition: Brand New Part Number: PPM-4 Condition is "New". Shipped with USPS Priority Mail.