Box Spark Arrestors with Flue Cap Designed to mount to chimney masonry thru corner feet. Optional spoked kit available for internal flue mounting. Made from woven 13 gauge galvanized wire, 1/2 in centers. 14 gauge steel cap. Black powder coat finish. Custom sizes are available. Model No. Description 1541 Spark Arrestor, Small, 14 x 18 at corners 1542 Spark Arrestor, Large, 18 x 22 at corners 1543 Mounting Kit, Small, 11 x 17 spokes 1544 Mounting Kit, Large, 15 x 19 spokes