RKI Instruments RI-215D is a sample drawing type CO2 monitor that detects CO2 gas and provides an output signal proportional to the concentration of the gas. It has six types, each with different measuring ranges and output signals. The RI-215D can be used to control ventilation or activate alarms based on CO2 concentration. It features an easy-to-read LCD display, adjustable alarm point, and various output options. With regular maintenance, the RI-215D is a reliable and accurate device for monitoring CO2 levels in various applications.