Retekess TT116 Wireless Tour Guide System, Translation Device, One Key Mute, Assistive Listening Device for Tour Guides, Church(1 Transmitter 10 Receivers)

I have an AV Production company that has a large set of the name brand devices which sell for $400/receiver. I recently had a triple booking over this past week, and while I could split my expensive set into two I needed a third system to cover all my events. Since one of my events was much more basic, I decided to give these a try instead of springing for more of the expensive ones. The price was too good not to try.I was simply blown away by the quality of the audio on these. We used the line-in port to feed the transmitter from our sound board, and just clipped the transmitter pack to a mic stand about 7 feet off the ground. No antenna boosting or anything like that - plug and play. I could walk hundreds of feet away and listen to static free high quality speech and music on all the receivers. We used these for the Spanish language interpreter at the event, and the attendees who utilized the system were all very very pleased with the sound quality and ease of use.For our setup, a few notes: My rave review is utilizing our system of a professional audio mixer with a professional audio engineer, outputting excellent quality audio directly into the "line-in" on this device. No settings needed to be changed on the device. We did provide reasonable quality headphones with each pack to all of our users - which is something we do for all these types of systems as the single earpiece is not always appreciated by the people who need to utilize the interpreter systems. So while I strongly recommend this product, I did not test or use it with either the included mic or the included ear-pieces. We use the very basic Sony ZX-110 headphones with them, and people are very happy with the quality. Our Mixer for this event was an Allen&Heath DLive.Because it is hard to find on the listing: These devices do input and transmit/playback stereo. They operate on 902-928Mhz band, which is totally fine/legal to use in the USA. They have 2 inputs on the top, one for mic (with a very basic pre-amp) and one stereo 3.5mm TRS ("Mini Jack"). This jack can take a regular headphone type cable input. We did not need to scan, sync, or setup our devices in anyway when they arrived, they were good to go. Each unit - both transmitters and receivers - ships with a retractable USB-A to USB-C cable for charging. I did not test to see if these cables are capable of data transfer, but I doubt it. Charge only. They do ship with basic 1-sided ear sets, I did not test those ear-sets for quality. The units will operate while plugged in to charge, so you can use them while they are plugged in for longer events. I did not really test the battery life, but we did not have anyone say their battery died during this event. We had three back to back to back 8-10 hour days, but I do not know if the Spanish language translator was actually translating/ broadcasting for the entire time.From my use, I really like and strongly recommend this system. I like it for the ease of use, great price, and for the quality of the audio. I am really happy with them, and my client was too. I will likely get a few more sets to have on hand.