Airtight Damper construction to DIN 1946 T4 Smooth Post Blade damper movement Heavy Duty Cast Aluminium precision gears 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 23mm and 40mm Height in 165mm - width in 50mm increments Works with all CMR actuators and controllers CMR standard 24 month warranty 30 Years field application experience