I'm using Selkirk DSP double wall stove pipe and I need a section about 9 inches in lenght. They make 6 inch sections and telescoping sections that start at 12 inches. Selkirk also makes DCC pipe that is adjustable from 2.5 to 5 inches. That would give me the correct lenght if I combine it with a 6 inch section. Is the DSP stuff compatible with the DCC stuff though? Are there any other brands that are compatible with the Selkirk DSP? Is there any other way to get a 9 inch length of double wall? This really shouldn't be that complicated....