Essential CO2 Test Tool: Fish tank co2 drop checker can help you monitor co2 content in the aquarium and keep the health of your fishes and plants. Application: CO2 drop checker is suitable for aquarium and fish, especial for ornamental and breeding of aquatic plants and tropical fish. Premium Material: 2 Pack aquarium co2 checker is made of high-quality glass material, non-toxic and odorless, safe and durable. Transparent color, easy to observe and clean. Proper Size: The size of aquarium co2 monitor is 5*5cm. With suction cup, easy to attach to the wall of fish tank. Easy To Use: Drop 5 drops co2 indicator solution (not include) and some aquarium water into aquarium co2 detector, and then attach to the inner wall of aquarium. (You need to install the monitor below the water surface about 10cm) Feature: Aquarium co2 tester is an indispensable tool to monitor the co2 content and keep the health of your fishes and plants. CO2 glass drop checker is made of high-quality glass, safe and durable. With suction cup, can easily attach to the wall of aquarium. Simple Step: 1.Clean the wall of aquarium 2.Drop 5 drops of co2 indicator solution into the co2 drop checker 3.Pour monitor to let the co2 indicator flow into the test area 4.Use a straw to fill the aquarium water with the test solution area to 1/2 5.Turn the opening face of co2 drop checker down 6.Attach to the wall of aquarium and monitor should be installed below the water surface 5-10cm Specification: Material: glass Size: 5*5cm Weight: 48g Package Includes: 2*co2 drop checker Satisfaction Guarantee: If you have any problems of our product, please contact us by email for replacement or refund.