http://www.coaxseal.com.
___________________________________________
And also Scotch Coax-Seal , 1 inch wide , 10 feet long. Mastic Tape#2229.
And Scotch Rubber Mastic Tape , 1 inch wide , 10 feet long , #2228.
I have been using the Scotch Rubber Mastic Tape for many years.
When it is put on it works and seals so well , the only way to get it off is to cut it off.