Damper Caps and stack Parts Made in the USA Direct from the Manufacturer. This is a Up-flow Damper Cap or Automatic Roof Ventilator. Designed for use in Paint Spray Booths or any other powered exhaust stack. Manufactured right here in Detroit, MI. with USA steel. Manufactured in 18″, 24″, 30″, 34″, 36″, 42″, and 48″ diameters. All Hand Crafted using 18 ga. Galvanized, G90, USA Steel, Sheet metal formed and rolled with pipe lock hammered seams, Bolted and Welded construction. Damper lids are gravity actuated by exhaust duct airflow and closes on exhaust fan shutdown. The product is manufactured by SSM Industries for over 50 years in Detroit, MI. United States along with other stack parts we manufacture here in our plant. This Damper Cap or Automatic Roof Ventilator comes with a 1-year manufacturer warranty for Workmanship. The item weight varies depending on the Damper size. Order according to your stack diameter requirement as we list them. Shipping will need to be LTL shipping because of size and weight. Shipping will be a additional cost. We will package for LTL shipping and assist in either using your shipper or we will get you a cost for the additional shipping. We usually ship within 2-3 days of the order.Please send us your ship to zip code, size and how many caps you require and we will send you shipping cost and how to proceed with purchase.