I own an Auto Glass Business and I know CRL makes quality sliders for trucks, I would Not have aftermarket windows installed. Most conversion windows are installed by cutting the hole and a frame fits the hole from the inside where screws are attached about every 4 inches or so, The screws fit in a grove on the frame of the glass pressing them together.... Everyone I have ever done was simply sealed by a piece of foam. Next conversion van you see, look at the rust that around the conversion frame. This is because when they cut the hole, no one covers the bare metal, the Foam holds water like a sponge and the metal starts rusting pretty quick, There is a Sprinter around town a shop installed 2 back glasses and this thing is so badly rusted, Its a white van and the rust marks are really bad. Since I started my own business, I do not do conversion windows so maybe they changed how there done but I cant see any other way really...