The Deluxe Charging Kit from Plantronics is giving you an option to simultaneously charge an extra battery while charging your Plantronics Savi W440 or W740 headset.
This base charger/battery kit allows you to charge an extra battery while you are using the wireless headset. It is very easy to use – just pop the battery into the side door of charging cradle and it charges while you are using your wireless headset. It comes with charging base cradle (with side door for 2nd battery) and spare battery. Battery is fully charged in 3 hours and you can use it for 7 hours of talk time.
Important note: You can replace the battery during the call, without losing the call, as long as a charged battery is reattached in the next 5 minutes. This allows for unlimited talk time.