Outdoor Indoor Bluetooth Speaker, 24H Playtime Portable Home Wireless Bluetooth 5.0 Speaker with Stereo Bass, up to 100 ft Bluetooth Range, IPX7 Waterproof Mini Bluetooth Speaker

I liked these speakers, especially after breaking in the battery, now I get about 12 hrs on normal volume using them. I love that they can be paired to make a true stereo sound system you can balance in your app. Once paired, raising the volume on one raises it on both, so any balance needs to be done through your app or your system. Sound is good %26 quality for these size speakers and offers good amplification enough for a large room. They do start distorting at about 85-90%, Hint: Battery will last longer if volume is increased at source rather than on the speaker, not sure why. Bluetooth connection could be stronger, in a cluttered area only held connection to my Lenovo laptop about 30 feet. I haven't tried using the TF Card mode and the instructions give no specs on the size card that can be used. Be prepared to use your phone as a magnifier to read the tiny print in the usi=er manual. Here is functions as far as I can tell: SMALL TRANGLUAR M12 SPEAKERS O long press(2s) turn on/off; SHORT PRESS PLAY/PAUSE; DOUBLE PRESS - BLUETOOTH CONNECT/DISCONNECT SHORT PRESS - VOLUME UP; SINGLE PRESS - NEXT TRACK; DOUBLE PRESS LINK/UNLINK 2 SPEAKERS - SHORT PRESS VOLUME DOWN; SINGLE PRESS - PREVIOUS TRACK

I bought a pair because they can be linked via TWS to get true stereo sound and separation. Once liked, via pressing the symbol quickly twice, they will stay linked once connected and powered on in the future and changing volume on either affects both, so if you want to change balance volume, you'll have to do it on the app on whatever Bluetooth device is playing the sound. That said, sound is great for size and amplifies significantly before becoming distorted( at about 90 %). I have yet to check the TF card mode, nor was there any documentation(you'll need a magnifier to read it) on TF card size or format limitations. I would assume that all sounds would have to be in the root directory, although, since I didn't check it, may show on the system as a drive over Bluetooth so you can select a directory. Charging took about 3 hours for about 8 hours of play time at medium volume(higher volume requires more power which will decrease play time). So there was reasonable charge/play benefit. No lights except the Bluetooth connection blue light(impossible to see on black speaker but shows through on red one) and charge light, which goes off when charged.