Presenting the Panasonic WhisperGreen ceiling mounted ventilation fan series from Panasonic. Panasonic continues to spearhead a revolution in ventilation excellence with the introduction of the WhisperGreen series ventilation fan.  SmartFlow enabled, which means the fan is designed to perform at a constant CFM, which was nearly impossible until now because of duct length, elbows and other factors that hindered its ability to perform at rated levels.  When a WhisperGreen faces static pressure, its speed is automatically increased to ensure that the desired CFM is not compromised.  This allows the fan to perform as rated and more importantly makes for easier installation, because the installer no longer has to worry about compromising the fan's performance. The VKS fans feature a built-in variable speed control.  The first fan released the FV-08VKS1 will allow the fan to run continuously at a pre-set lower level (30-80 cfm).  The fan then elevates to a maximum level of operation (80 cfm) when the switch is turned on. Feature on the VKM models, are a SmartAction motion sensor.  The sensor will automatically activate the fan whenever someone enters or leaves the room, so there's rarely a need to manually turn the fan on or off. Dimensions: 10 1/4" square - unit depth 7 7/8" - grill 13" x 13"