This CO2 Indicator features an All Angle View so you can regularly and accurately monitor the CO2 level in your aquarium, from any angle! With the reusable color chart sticker, you will quickly be able to know if the carbon dioxide level in your aquarium is at the appropriate level. Most importantly, this Indicator is built with a smart design, to ensure no solution spills into your pets home! 1.5" x 1" x 1.75"