Made of upgraded thick PP material, this manual volume damper offers high hardness, anti-drop and abrasion resistance, resisting deformation, and moisture for long-term service. The flame retardant structure helps improve safety and fade resistance in demanding HVAC environments. The inner of the damper is smooth and flat, helping reduce airflow resistance and noise while enabling rapid, efficient ventilation. This streamlined structure promotes stable air distribution, improving comfort and supporting better overall performance of your HVAC air balancing system. Material: thickened plastic for enhanced rigidity and impact resistance; Inner Diameter: 160 mm / 6.3 inch fits standard ducting; Overall Size: 198 x 4 mm / 7.8 x 0.16 inch (L*T). Package includes 1 x duct manual volume damper for HVAC systems. Designed with a convenient side rotary handle, this airflow backdraft damper lets you precisely adjust air volume at multiple angles. The handle is easy to grip and operate, allowing smooth regulation or complete shutoff of airflow without tools, ideal for frequent balancing adjustments. Installation is simple: just slide the manual volume damper into the round duct or pipe, then secure firmly with appropriate pipe clamps and sealing tape to prevent air leakage. Confirm the inner diameter before ordering; recommended operating temperature range is -10°C to 70°C for optimal use., Weight: 2.20462262 pounds, Manufacturer: Teuypty