The 457 Headset design is based on the HD3 to make it an easy transition for your customers. Changes were made to noninteractive components, so the functionality will be the same as the HD3 headset. The new 457 is also compatible with the existing Attune I and Attune II headsets and can be utilized in combination with the customer's installed headsets. This will benefit your customer by allowing them, when needed, to replace headsets one at a time, saving them substantial “out of pocket” costs. The current battery (WX-SB100) and Battery Charger (WX-Z3040A) will remain and are sold separately.