The outlet is unbelievably easy to put on the gutter, simply stick the 90 degree tab into the bead of the gutter, roll it back and under the gutter. It will click into place and you finish with securing the tab down over the backside of the gutter. No caulking, no rivets or screws are needed to make this product work. The outlet is almost 9" wide on the gutter, allowing for a 6-7" whole to be cut in the gutter. The outlet guarantees free flowing water without any obstructions at all.