The No 503ATD metal Air-Tite starting collar with damper is available in 12 sizes from 4 in through 20 in. Air-Tite series starting collars have a gasketed flange to ensure the best possible sealing at the joint.
M&M Start Collar, Air-Tite Round, Series: 503ATD, 8 in Size, 5-1/4 in Length, Steel, Galvanized