This is a highly flexible amateur FM transmitting/receiving antenna, which consists of 4 adjustable-length telescopic antennas and can be placed outdoors. Compared with a single antenna, it has higher gain and transmission efficiency, and can significantly increase the transmission distance or improve the receiving sensitivity. The length of the four vibrators of this GP antenna can be adjusted according to the transmission or receiving frequency. It is more flexible than the GP antennas with fixed-length vibrators sold on the market. The vibrator length can be freely stretched within 20~112CM to adapt to a range of transmission frequencies. The vibrator length of this antenna can be accurately set to 1/4 wavelength of the transmission frequency (to achieve the highest transmission efficiency): vibrator length (meter) = (300/frequency)/4. If the transmission frequency is 100MHZ, the length of each vibrator is: (300/100)/4=0.75 meters. This GP antenna is an umbrella structure, that is, the main vibrator is stretched vertically upward, and the other three ground grid vibrators are pulled out horizontally at a 45-degree angle downward. When using it, be sure to adjust the length and angle of each vibrator, otherwise it affect the use effect or even burn the transmitter. Remember! Due to different batches, there may be differences in product appearance, color, and printed text, which not affect the use. Color: As Shown Material: PCB Package Contents: 1X Comet GP antenna (without coaxial cable) 1X 50Ω Q9 (BNC) male coaxial feeder connector 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.