Rob

The antenna comes with a rubber base gasket and a little tube of silicone. I haven't hade any problems with leaking. Let me know if you have any questions about installation. I installed mine about 1.5" from the rear of the roof. I had to cut about an inch and a half square cuttout through the middle of an inner brace. I did this with a dremel/cuttoff disk. With that removed There is a pre-existing hole in the main rear roof brace that looks like it was made for an antenna (like on the 968's. I then drilled a hole right in the center of that hole to mount the antenna. I could take some digital pictures if you need them.