Black Beauty HD (Heavy Duty) 160-40. Is a Next-Generation Common Mode Choke. That is optimized for the lower portion of the HF spectrum from 160m up through 40 meters. It provides more Common Mode Rejection (CMR) in that range than wideband chokes that cover the whole spectrum. It provides 53 dB of CMR on 80 meters, 50.7 dB on 160 meters, and 44 dB on 40 meters. Black Beauty chokes are ventilated to keep the ferrite core cool. This allows it to handle 80% more power than a sealed unit.Read More