B) Disadvantages: More expensive than Do-it-yourself and will involve scheduling delays based on the availability of the company companies. Howdy! To install the 39-310 clip, you need to slip it on to the underside/inside of the glass louver. Each ends within the clip have an angle bent in opposite directions; https://bookmarksoflife.com/story4238864/the-ultimate-guide-to-how-to-install-securit-glass