Combined ATG Damper and FGG Flowgrid Airtight Damper construction to DIN 1946 T4 Compact Constant or Variable Volume control Sturdy Actuator drive spindle 12mm Ø Embedded quality seals in damper blades Special moulded seals on each blade end Brass bearings with 'O' ring seals on drive shaft Standard Frame sizes 20mm and 30mm Height in 100mm and width in 50mm increments Works with all CMR actuators and controllers CMR standard 24 month warranty 30 Years field application experience