The fire guard is installed to ensure proper draft by creating negative pressure in the chimney flue and preventing reverse draft. The fireman's cowl should be mounted on the top of the chimney, directly on the pipe or using a base.
Stainless Steel Chimney Self Adjustable Cowl Duct Pipe Metal Spinner Pot Guard
Stainless Steel Chimney Self Adjustable Cowl Ventilation Duct Bird Guard Fireman
Stainless Steel Chimney Self Adjustable Cowl Ventilation Duct Pipe Bird Guard
Round Chimney Cap Stainless Steel Chimney Pipe Cap Universal Chimney Cap
Stainless Steel Chimney Cowl with Clip Rain Protector Pipe Cover Chimney Pot Cap
13" x 13" Chimney Cap Stainless Steel Chimney Cover for Fireplace Vent Pipes