The rectangular bottom of these base stacks are 4″ deep x 18″ wide.
The diameter of the mouth on top is 8″.
The base stack is 34″ tall.
There is a collar on our Corsair and Silverplate arches over which the base stack will sit. This collar has holes pre-drilled in it to accommodate folks who want to bolt down their base stack. We recommend using #10 stainless steel bolts to accomplish this. Bolting the base stack is not necessarily imperative if it is already supported by stack pipe that is going through the roof.