Quick overview from the supplier:
Bluetooth Headphones Panasonic RB-M300BGE-K, Black, Over size, 50 Hours Playback
Weight: 296g; 50 Hours Playback: On a full 4 hours charge, plus quick 15 minutes charge for 3 hours playback.
https://www.panasonic.com/mea/en/consumer/home-entertainment/headphones/overhead/rb-m300b.html
