Charging One is simple.
Just plug the USB charger that's included with your stethoscope into the 3.5mm headphone jack. One uses a rechargeable Lithium Ion battery that allows for around 4 hours of continuous listening (approximately 100-125 patients) per charge. Battery level is indicated by an LED on the 1-10 volume scale when the unit is manually turned off.
A thorough charge cycle can take as long as eight hours, however your One will have almost full capacity within four hours. If necessary, you can use the stethoscope again after just 30 minutes of recharging. Always charge battery before fully depleted!
The One operates on AC voltages worldwide and has a voltage range of 100-240V, using a US-style flat-pin plug. In some countries, it may require a plug adaptor.
When charging, the Battery LED will flash. When the battery is fully charged, the LED will stop flashing.
To find out more about charging, please see the Battery Charging section of the User's Manual.