What do the battery lights mean on my Philips Sonicare AirFloss?

When on the charger, the charge indicator flashes green to indicate that the appliance is charging.

Note: When the charge indicator flashes yellow, the battery is low and needs to be recharged (fewer than 3 uses left).

How long does a full charge last?
When it is fully charged, AirFloss has an operating time of up to 2 weeks (or 14 uses).

When the handle of your Airfloss is on the charger, you will see the following lights on the handle (also shown in the image below):

1 solid green LED = 33% charged.
2 solid green LEDS = 66% charged. 
3 solid green LEDS = 100% charged.

Note: When it is fully charged, your AirFloss Pro/Ultra has an operating time of up to 11 days when it is used in single burst mode. When the charge indicators of your Airfloss flash yellow, this means that the battery is low and you have less than 3 uses left. In this case, please charge your Airfloss.