I am trying to locate the proper adapter for a ceiling box that I believe has 7" DuraLock or similar insulated pipe. I want to adapt the 7" pipe in this box to 6" standard black stove pipe coming out of the box. The ceiling box is round and was installed in the 1980's. There is a trim piece welded on the bottom of the box with approximately 7" diameter hole. I have a new Smartstove with a 6" chimney connector that is replacing a home made barrel type stove that was in the house when we bought it. The old stove was connected to the ceiling box incorrectly. Any help or suggestions would be appreciated.