ok I have bought many sets from the U.S.A. to use here in the U.K. I use a step down transformer for the purpose, i replace the present day bubble lights when they blow. im not sure if they are c7 or c6? well i open the case and replace after the holidays those that have blown on my set up in the uk, does anyone know where i can purchase spare bulbs now please? or where I can purchase modern day bubblers cheap for me here in the U.K. Thanks.