Your P100 can be turned off by sliding the Power & Pairing switch on the left headphone all the way down.
The P100 also has the option of automatic power down (APD). The length of time that it will take for the P100 to power off when they are detected as connected but not playing audio can be adjusted within the Melomania Connect
Note: APD requires the P100 to be detected as inactive and not in use. APD will still be activated on the ear buds even if they remain connected to a device.