Model 0310V/H Wide Frame Static Curtain Fire Damper is UL approved for use where local building codes require the protection of HVAC ductwork penetrations in walls, partitions or floors that have a fire rating of 2 hours or less, classified for use only in static "fans off" systems where the HVAC system is automatically shut down in the event of a fire alarm. The wide frame allows for fewer blades and is ideal for use when maximum free area is desired in situations where space or design does not yield room for a Type B damper style.