Pellet stove pipe

[Thechap]

I am trying to locate a three inch "T" clean out with and increase to four inch in. I will be using four inch pipe to the 6 inch exhaust pipe at the ceiling. I'm hoping to find a single wall "T" instead of the double wall. Does anyone know where I can find one? I also need (can't find) an adapter I can use to join double wall pipe to a single wall pipe. I really hope someone can help me find these items.