8mm is deceptively small, like the size of an eraser head, make sure it's the right size for you. 4 out of 10 blisters were not flush to the bottom and did not connect due to plastic debris not being cleaned properly. I had to sand the floors myself to get everything even. Please note it doesn't come with backing glue, you need to use your own. In general it serves its purpose. Used in place of the camera's hot shoe.