Flat Spark Arrestor Sized to fit on top of rectangular flue tiles. Cut of woven 13 gauge galvanized wire, 1/2 in centers. Packaged in bundles of 5. Custom sizes are available. Model No. Size Model No. Size 1501 8.5 x 13 1511 13 x 17 1503 8.5 x 17 1513 13 x 21 1504 10 x 14 1515 17 x 17 1505 10 x 17 1517 17 x 21 1507 10 x 21 1519 21 x 21 1509 13 x 13