margot5 years ago000How large must the diameter of the cut-out in the window be? Kind regards Show in original language (German)Capo425 years ago-101 Helpful answerHello According to this page here (must scroll down a little) https://www.surepetcare.com/de-de... The diameter is 300mm for glass mounting. Greetings CapoShow in original language (German)Comment1 comment