Rapit Regulator - 8085 The Duro Dyne Rapit Regulator is an inexpensive rattle-free option for quick installation on regular and splitter dampers. Simply hammer onto the damper blade and insert into the duct work; job done. Sold in sets of tenFeatures: -Speedy hammer on application. -Heavy gauge galvanised steel. -Fully retractable threaded wing nut. -Clear marking of position.