Got it in White. While it's a bit unclear, it seems to support BT 5.3 and the various standards associated with that, but I've seen it as 5.0 (manual), 5.2 (the 1Mii web page) and 5.3 here at Amazon.

The Apt-X HD is really nice for getting good quality BT audio out of my Windows box for Spotify (given the limitations of BT and Spotify, etc. etc.), and the Mac laptops connect via AAC (as usual). I've got an old Klipsch powered desktop speaker set (ProMedia 2.1 THX) plugged in via the 1/8" jack, and it works quite well with the 1Mii ML300. The single button per "connected device" takes some getting used to, and the manual is, as usual, kind of confusing. Between things on this Amazon page, the manual, and some experimentation, I was able to mount my Mac laptop and Windows desktop simultaneously and they switch off pretty easily.

I did not test the transmit, as I also use Sony headphones so got a beefier Fiio BTA-30 Pro (6x the price of this gadget!) to allow the Mac to transmit LDAC. While that's a nice device, this 1Mii can do much of the same (at least up to Apt-X), but doesn't support all the fancy optical and powerful DAC features of the Fiio.

I haven't tested the 1/8" jack signal coming out to see how clean it is, but I don't get tons of crackle or hum at high volume with no signal (but not zero). I also have turned the source volume up and output seems basically ok, but I don't expect much from a tiny device at this price.

Biggest hassle: if a signal doesn't show up for a while, the ML300 just shuts off, even when plugged in. This means that if you don't use your computer for a day, the thing just turns off. You have to manually turn it off and back on to RX to re-awaken it. This means it can't be an in-wall or otherwise hidden option, and also means you need to keep it reachable, which kind of sucks. I expected that if it's permanently charging, it wouldn't ever shut off unless I turned off. Also, it seems to "sleep" the speakers when the audio pauses or stops, making a loud "click" sound which is just sloppy electronics.

So, it's kind of minor, but also frustrating to have to dig the thing out and turn it off and on again when it powers down. It boots quickly and reconnects quickly, but it's just an avoidable "feature". Making this settable would be much appreciated in a future rev.

But for the price, you get Apt-X HD (and LL if your device supports it) which is a nice add in this price range, as well as a tiny size. The one-button dance and auto-shutoff are hassles, but at this price point, it's not hard to overlook them, at least when I'm not bumping my head into the desk as I yet again cycle the switch.

Overall, a good buy, esp at this price.

I bought this for a small TV with inadequate built in speakers. Works great with a portable speaker or ear buds. Initial pairing was frustrating until I read and followed the directions. Don't know about battery life as I plugged the usb charger into a port on the back of the TV. It will turn itself off/disconnect if there is no audio going through it. Just slide it off & back on. I have only used it in transmit mode.

Bought a second one to use with earbuds on a couple of upcoming long haul flights.

I wanted to have a wireless monitoring setup. This Bluetooth transmitter is a key component. The latency is low in my cheapest headphone but the delay is there in more expensive headsets, how ironic.

The Bluetooth protocol is 5.3 so i think just finding a compatible headset will make this a success.

The good thing is setting up Bluetooth headphones is really easy to set up. I just hold the two devices next to each other and they pair within seconds.

This is probably a less used solution but it helped me tremendously in skydive training. Being able to hear the radio under canopy was essential for safe landings. I am a hearing aid wearer and I wouldn't accept that as a limiting factor. I tried several bluetooth ear buds and even a combination of them with this device on the radio. When I went to a set of speakers in the helmet and this device as the receiver and another one connected to the radio, I found the pair to be a solid and reliable connection that has yet to fail me. Since the radios are mono audio out, I added a mono to stereo adapter and now I have stereo.

Another application for these will be to connect the audio altimeter to the speakers and allow me to carry the audio altimeter in a jump suit pocket. This will help perform maintenance as well as have superior audio in the helmet in both ears instead of just one. Can't say enough about how this product helped me.

I upgraded to noise cancelling earbuds and bought this device to use on an airplane. I paired the device at home by using transmit mode plugged into an earphone jack. My earbuds are the Sony WF1000XM5s. Contrary to many reviews, for these earbuds it was easiest to leave my phone's Bluetooth connected and use the app on my phone to allow multiple connections and put the earbuds into pairing mode. Pairing went smoothly. I may update this review after my flights.