Delta Breez SIG110H Signature 110 CFM Exhaust Fan with Adjustable Humidity Sensor and Speed Control Virtually silent at less than 0.3 sones An indicator light underneath the grille assures you that this quiet fan is running Adjustable humidity set points between ~50% to ~90% RH When humidity is above the user-adjustable set-point, fan runs at full speed (110 CFM). When humidity is below the set-point, the fan runs continuously at a pre-set lower level (0, 60, or 80 CFM) ENERGY STAR Most Efficient for efficient cost-saving operation