According to the initial press releases and the first tests, it seemed that the Apple AirPods Max headphones needed a case in order to switch to low-power mode — otherwise, the already small battery, which lasts for a maximum of 20 hours of operation, would continue to be spent, since the headphones do not have a turn-off button.
However, Apple explained that the case is an optional element. The headphones automatically switch to low-power mode five minutes after you stop using them — even without a case. In the case, the headphones will go even into a more serious power-saving mode after 18 hours, which disables Bluetooth and the function of searching for missing devices.
For devices without a case, this mode will be disabled after 72 hours — the period has been extended specifically in case of theft of headphones. However, there is still no way to completely turn off the headphones.