7-1/2 x 7-1/2 x 9-1/2 x 9-1/2" chimney cap for rectangular fit. Welded-wire spark-arresting 1/2 x 1/2" mesh reduces clogging, soot and creosote build-up. Meets all fire codes. Heavy duty 24 gauge steel top, epoxy powder finish. Installs securely using only a screwdriver.