Silencers Ø 50 mm, suitable for all AERIAL type AB noise boxes and HB side-channel compressors. Noise reduction down to 7.5 dB, depending on compressor type. Two silencers can be arranged in series for particularly effective noise reduction. This double flow system is inconspicuous, does not impede the performance of the fan, and smoothes the turbulence of the air current very effectively.