Review on IGPSPORT Out Front Computer Handlebar Mountain by Chris Dildine

I have three bikes. When trying to fit them I found that the diameter of the part that goes around the handlebars on one of my three bikes is too large. The diameter of the front bracket is about 30-31mm and my bike is 22-26mm in diameter. I think my bikes are typical. There is no other way to tighten or fit the Out-Front to my bikes other than to find a 5mm or 6mm strip of rubber to fit around the handlebars, which is what iGSport support suggests. I don't know which handlebar fits Out-Front. I wonder why they didn't develop it for all handlebars?