The only difference is the heat range. The 7s are one grade cooler than the 6s. If you are using the 6 version and the insulators look white after use and you have trouble getting full boost, especially in hot weather, switch to the 7 range. If you are using 7s and the insulator is getting dark brown or building up deposits, go to the 6 heat.
Incidentally, it varies by manufacturer if increasing numbers are increasing or decreasing heat. Most of them use higher numbers for higher heat.
John
Incidentally, it varies by manufacturer if increasing numbers are increasing or decreasing heat. Most of them use higher numbers for higher heat.
John
