In the box there is a warranty card for a 2-year warranty from the manufacturer with a serial number. The sound quality is not as good, but this is normal considering the features of the headphones. As already mentioned at high volume, everything (everyone) is heard, so the drivers will "tickle" your ears. The headphones do not turn off themselves after a long period of inactivity, but I'm not sure if this affects the charge level. For my purposes I'm happy with my purchase.
Upgrade Your Music Experience with XiaoMi True Wireless Earphones 2 Basic - Longer Battery Life and Superior Sound Quality (White, International Edition)
341 Review
Black Huawei FreeBuds 3 Wireless Bluetooth Earbuds for Superior Sound
276 Review
🎧 HUAWEI Freebuds 4i: Wireless Earbuds with Active Noise Cancelling & 10H Battery Life in Black
279 Review
Upgrade Your Audio Experience with Samsung Galaxy Buds+ Plus: True Wireless Earbuds with Improved Battery and Call Quality in White, including Wireless Charging Case and Velvet Pouch.
320 Review
Panasonic RP-HS46 Slim Clip-Type Earphones in White: Quality Sound On-the-Go
76 Review
🎧 Experience Unmatched Audio Quality with Marshall Major 4 Bluetooth Headphones
104 Review
Sony MDR-ZX310AP ZX Series Blue Wired On Ear Headphones with Mic: Immersive Sound Experience
48 Review
Black Panasonic RP-HJE125E-K Wired Earphones 🎧 with 3.5 mm Jack
359 Review