they make a clear ... one named ..... invisible .. it works great also... my favorite local one is a home depot item... called roof and flashing PL S30.. it is slow to cure ... a day or more.. it is black... because it is a flashing compound it has great stretching to keep it stuck to different materials ... it doesn't get brittle... good outside summer or winter.. it is a polyurethane item... not a silicone
