dB (decibel) – what does it mean?
Units of measurements called decibels (dBs) are often used to denote how much reduction (attenuation) of signal strength has occurred after shielding has been installed. In other words, it indicates how effective that shielding has been.
The higher the number of dBs, the greater the shielding effectiveness.
10 dB = blocks 90 %
20 dB = blocks 99 %
30 dB = blocks 99.9 %
40 dB = blocks 99.99 %
50 dB = blocks 99.999 %
60 dB = blocks 99.9999%