I just received this thing from AliExpress, with the very specific idea of using it as a stereo FM tuner and Bluetooth music device for an old-school Harman Kardon integrated amplifier. I naturally assumed that "FM Radio" meant "stereo FM Radio" but of course that was a mistake. The device itself is stereo - for sure - for everything except the tuner, which is mono. And that makes it useless to me. Comes in the original box with all the bits. Tested for about 30 minutes.

BUT - I can't complain about anything else! This tiny thing is feature packed, and the included instructions show it to function exactly and precisely as it says it should. As a preamp it has Bass and Treble controls which show their +/- dB value when adjusting them, a nice touch. The remote control works, and is full-featured.

The unit is TINY! Like pack-of-cigarettes size. It's fairly weighty though, which makes sense for all the input and output options it has. It has great value in simply being a tone-controlled pre-amp device you can connect via RCA to any legacy audio gear, to stream music from your phone.

And weirdly, it has a 1200 mAh battery built in - so you can take your Bluetooth streamer mobile! The Bluetooth works like it should, although I only tested its RX side, not its TX potential.

You can search for "M9 Pro TX/RX Bluetooth" and locate all the details for it. But I have pasted in below what the page about it says:

Product Name: Multi function Bluetooth audio adapter Product Model: M9 Pro (with FM radio function) Bluetooth V5.1 - Chip: MVSILICON Battery: 3.7V/1200mAh Charging Time: ~1.5 hours Using Time: Listen to music for about 8-10 hours and stand by for 30 days Transmission Range: 30-50m (barrier free) Interface: 3.5mm AUX/2RCA/USB/TF/6.5mm MIC Power Input: USB-C (5v) Support Protocol: A2DP/AVRCP/HFP/SBC Support Protocol: MP3/WMA/SBC/WAV/DTS/A52/FLAC/AAC/AIF/AMR/APE Product Color: Silver black Product Material: High strength fireproof - V0 PC (70%)+A