1. Ventilation Solution: Designed to fit 8' whirlybird turbine roof vent, round chimney cap and roof vent cap, our roof vent adapter enhances ventilation in shipping container or container storage, reducing moisture and heat, protecting cargo stored inside. 2. Precision Fit For Conex Roof: This container accessory is designed for Conex container roof with 3.5' rib, designed to prevent leaks, for retrofitting the ventilation system of container house. Before purchasing, please measure the size of your roof rib. 3. Time and Cost Saving: Roof vent kits save time and money. Includes positioning aid sticker, driver bit, drill bit etc. The corrugated base design allows it to be fixed on the Conex box roof without welding. 4. Weather Resistance: Roof turbine vent adapter made of steel with a powdercoated rustresistant finish to withstand harsh weather, duty design and durability.