Heat Robber measures 8"x 8"x 8" for added surface area to hold more heat in the tent and less up the flue. It includes a slide out spark arrestor (which can be cleaned from within the tent) that captures embers before they exit the flue, giving less of a chance of embers landing on the tent and creating fires. The Heat Robber is compatible with the 5" round straight pipe used by the Alpine, Timberline, and Spruce Cylinder Stoves. Heat Robber is meant to mount between the first and second pieces of pipe from the top of the stove. Made in America.