ANC™ - CT51-71 ANC™ CT51-71 SILENT ANC™ is an extremely advance study combining vacuum motor positioning, isolation and separated air flow. The result is extreme machine silence. Lower noise levels (down to 54 dB) are available when ECO SELECT mode is activated. Applied to: CT71 CT51 Benefits Amongst the lowest noise levels in the marketplace. Extremely low noise where silence is necessary. Does not disturb in crowded areas. ANC™WITHOUT ANC™
