12 cm wide and 16cm high glass domes with 6x 2cm holes, allows plenty of circulation. The idea came to me from frustration. I was going through an ammonia spike, I was doing everything I could to get it down including daily partial water changes, I couldn’t understand where it was coming from. I knew that adding more plants would help my situation but every time I added some from my other tanks, they would be devoured in hours. After a lot of head scratching, I came up with Growglass. They helped me restore my tank back to its former glory and they will help you too.