The QRM canceller plugs into the antenna's feedline from the without any other modifications to the radio. has built-in PTT controls, allowing the eliminator to stay connected during transfer. However, an additional auxiliary receiving antenna is required, such as a 2m antenna or just a few meters of wire in the shed. The two antennas pick up unwanted signals, causing them to be out of phase. The QRM canceller now allows adjustment of the phase angle as well as amplification to cancel unwanted signals before they reach the receiver front end! Aluminum , front and rear baffles: epoxy fiberglass board FR4 Colour:Black Material:Aluminum alloy Size:125x110x51mm, excluding the joint part Package Contents: 1 * Host 1 * PTT cable 1 * FM telescopic antenna 1 * Power cord 3 * F adapter UHF/SL16-SMA Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.