DuraVent DVL Double Wall Black Pipe Telescoping Section Size:6 in. x 40 in. to 68 in. The beautiful Ventis HE275CF Zero The beautiful Ventis HE275CF Zero Clearance Wood Burning Fireplace is a great option for an update or a new installation Size Lid Size Fits Flue Size 9 x 9 16" x 16" 6 1 2" x 6 1 2" to 9" x 9" 9 x 13 16" x 21" 6 1 2" x 11 1 2" to 9" x 14" 9 x 18 16" x 26" 6 1 2" x 16 1 2" to 9" x 19" 12 x 12 21" x 21" 10 1 2" x 10 1 2" to 13" x 13" 13 x 13 21" x 21" 11 1 2" x 11 1 2" to 14" x 14" 13 x 18 21" x 26" 11 1 2" x 16 1 2" to 14" x 19" 18 x 18 26" x 26" 16 1 2" x 16 1 2" to 18 1 2" x 18 1 2" Measuring for Your Stainless Steel Chimney Cap 018" outer wall Do not cut or trim