Features: 1. Convenience: The QRM canceller is inserted from the into the feeder of the antenna without any other modification to the radio. 2.PPT Control: The box has a built-in PTT control to keep the canceller connected during transmission. However, an additional auxiliary receiving antenna is required, such as a 2m antenna or only a few meters of wire in the shed. The two antennas receive unwanted signals, resulting in different phases. 3. Adjustable: Allows adjustment of the phase angle and amplification to eliminate unwanted signals before reaching the front end of the receiver! It is based on a completely innovative concept and cannot be compared with normal "silencer" performance. 4. Material: The material is excellent, the shell material is aluminum shell, and the front and rear baffles are: epoxy glass fiber board FR4. Specification: Connections: Main Antenna, Auxiliary Antenna and 3xBNC for RCA jacks for PTT are: approx 5.5x2.1mm Required power supply: 13.8V/150mA Size: about 124x113x51mm/4.88x4.45x2.01inch color: Black material: metal Notice: 0.5-1mm deviation between dial and knob pointer Package Contents: 2 x QRM Eliminator 2 x PTT Wire 2 x FM Rod Antenna 2 x Power Cord 6 x F Adapter UHF/SL16-SMA