clamps
lambro industries 3120l 4 x 8 inch aluminum flex ducting with clamp
features triple lock design for an airtight seal flame resistant durable includes 1 ul listed semi rigid transition duct and rigid 2 worm gear clamps for cloths dryers and can be used to vent 3 in or 4 in bathroom fans dimension 21 56 x 9 86 x 19 08 item weight 99 sku orgl12875