There is a wide assortment of rotary turbine roof exhaust vents. The majority are made of metal, generally either sheet metal or aluminum with typically a 12” or 14” louvered turbine that is either wind-driven or power-driven. Usually, a circular opening in cut through the plywood roof decking, allowing a pathway for the air to travel from the attic space, up the metal flue pipe to the turbine pulling the air from the attic. Normally there is a fairly wide piece of metal flashing welded or clamped around the metal flue pipe that is screwed directly to the plywood deck, which is then covered with roof felts and shingles, providing a watertight installation. Most turbine vents do not come with a standard wire screen to keep out fire embers. From inside the attic, you can install 1/8” or less metal screen up inside the metal flue to keep the embers out or, if your turbine has guards around the outside, the screen can potentially be attached to the guard struts around the turbine to keep the embers out (NOTE: If you have joints in the screen, be sure that the two pieces of screen overlap and the seam is tight and snug to keep out the embers).