Replacement RMILEC 20 channel R20NB4047 UHF LRS receiver for NB20 system. When the R4047NB20 receiver is combined with the NB20 system and set up to use all 20 available channels, your model parameters can be adjusted in flight, in addition, a pilot and co-pilot/aerial cameraman can work in conjunction with a single radio system. The new system offers broad improvements in both range and reliability, as any source of interference can be added quickly and accurately.