ITEM NAME:2Pcs Aquarium Crystal Glass CO2 Detector CO2 Concentration Indicator 3# Description: Maintaining proper Carbon Dioxide (CO2) levels in the planted aquarium is one of the most important factors in the health of the planted aquarium ecosystem. High quality material, stable and durable, including 2 styles. Useful tool for monitoring CO2 levels in the aquarium. Makes it easy to figure out the CO2 level in an anqurium. Use with CO2 PH Indicator(not included), long term monitor Co2 the color show :Blue - insufficient Co2,Green - sufficient Co2,Yellow - excess Co2. Specification: Material: Glass Size(LxWxDia): 60x35x10mm/2.36x1.38x0.39inch 80x40x10mm/3.15x1.57x0.39inch Package Includes: 2 Pieces CO2 Concentration Detector Note: Due to the manual measurement and lighting effects, there is a slight difference between the size and color from the above and the actual item. SKU: DMO0015371619393840.2 Pieces CO2 Concentration Detector. Maintaining proper Carbon Dioxide (CO2) levels in the planted aquarium is one of the most important factors in the health of the planted aquarium ecosystem. Useful tool for monitoring CO2 levels in the aquarium.