It's also a bad idea to use an existing roof vent for bathroom exhaust. You'll partially block the vent with the duct pipe, reducing the flow of cooling air through your attic. Moreover ...

【Anti-corrosion Material】This roof vent cap is crafted from high-quality iron, featuring a black coating on its surface. This effectively isolates the vent from the external natural ...

The plumbing vent is typically located on your roof. There are usually several fixtures connected to a single drain pipe in order to minimize the number of vents poking out of the roof.