Samsung CNH 4DB Series Technical Data Book page 50

Features & Benefits
Wall Mounted Type (Wind-Free™ )
Auto clean
Keep the inside of air conditioner clean and hygienic
automatically
The Auto clean time may vary depending on the status of the
product.
Quiet Operation
Wind-Free air conditioner work much more smoothly and
quietly. At its lowest level, it only generates 21dB(A) of
sound which is almost as quiet as a whisper
(*)
(*) Tested on the AC026TNXDKG/EU model in quiet mode.
ETO (Emergency Temperature Output)
Protect your computer room safely : Activate a backup
system when a unit has stopped due to an error or if
room temperature is above the specified threshold
[Display]
Requires additional components (MIM-B14) for each unit
7-Segment display
A large numeric display with clear and simple icons
makes it much easier to see the room temperature
and intuitively check the current status of your air
conditioner - even from a distance.
21dB