DuraTech 6″ Class A Chimney Pipe Wall Thimble adjusts from a minimum of 4″ to a maximum of 10″ wall thickness, and fits between standard wall studs. To accommodate thicker walls, the telescoping pieces can be extended up to 16″ with a field-fabricated extension installed. Interior trim ring painted black. Must be installed with DuraTech chimney pipe horizontally through the wall and extend 6″ into the room beyond the interior wall. (Black painted DuraTech is available).