USA version: The frequency range of these units is 537.0 to 558.6 MHz. These frequencies are shared with USA UHF TV channels 25 to 28. TV stations have room-sized transmitters that may produce an effective radiated power of one million Watts. Wireless microphone transmitters produce a mighty .01 Watt, for the most part. The inverse-square law is your friend, but be realistic. :) Consult the FCC DTV Reception Maps for your intended use location, and you will find reference received signal strength for the TV channels there. (Note that the displayed channel number is usually NOT the actual RF channel. Click the station on the list, and the truth shall be revealed.) To minimize interference, pick your wireless frequencies in the TV channels with the lowest reference signal strength. If you're using several wireless systems, the rule of thumb is to allow at least 1 MHz between channels, and space them irregularly to minimize intermodulation issues.Quirk: The F20 units have a quirk. I currently have four pairs, and this is present on all four. The "topping" part of the charge cycle seems to take a loooong time. If you want these fully charged, let them go overnight, or even longer.

Great product thank you!

No regrets,they work great for me. No more cable to ny mic preamp, game changer.

This is a great way to get old mics to be wireless. the battery life is pretty great in my testing, though my use is usually less than an hour or so so I am always able to keep them topped up. They don't add much additional weight to your mic which helps prevent arm fatigue and they're easy to get set up with.

My first unit stopped working, but the seller was responsive and sent a replacement no questions asked, so far the replacement has been working well for several weeks. This is the kind of thing that makes sound techs either breathe a sigh of relief or develop trust issues. Fortunately, this one falls in the not garbage category. The 150ft range is no joke, and it holds a solid signal even when surrounded by other RF devices. Works well for dynamic and condenser mics, which means fewer cables running across the stage for people to trip over. Ideal for anyone who’s tired of untangling XLR snakes at the end of the night.

I have a Shure SM58 (wired XLR), a Shure PGA58 (wired XLR), a ~$25 wireless mic, two ~$60 wireless mics (shared receiver), and an XLR transmitter and receiver. All the mics are tested by connecting them to a Behringer 1202F mixer, then to an amplifier and speakers.I rate the wired SM58 with an XLR connection at 100 points, and the wired XLR PGA58 at 80 points.I connect my SM58 to this wireless adaptor. The XLR wireless adapter performs poorly and produces a lot of noise. Even when the transmitter and receiver are turned on without connecting a microphone, there’s noticeable noise. Additionally, its XLR connector is not compatible with the SM58 or PGA58, and cannot be locked. At $150, the price is clearly too high, as the performance is similar to the ~$25 wireless mic (even when connected to the SM58). So, I give it 1 star.

I tested these all over the house and even out into the garage with no dropouts. Took them to a gig and had mass quantities of drop outs. I guess the jury is still out. Maybe had a bad channel or frequency. Sound quality is great as long as they are working. Range is soso to this point.

I purchased 4 sets. They all work well. Plenty of Battery life, and range. I use them for video recording. Sound is very good.