200mAh 504374, BATT-03 Battery Replacement for Sennheiser DW Office, DW Pro1, DW Pro2, MB Pro, OfficeRunner, SD Office, SD Pro1, SD Pro2 Headsets Replacement for the Following Battery Model/Part Numbers: BATT-03, BATT03, 504374. Compatible with the Following Sennheiser Wireless Headset Models: DW Office, DW Office ML, DW Pro1, DW Pro2, DW Pro2 ML, MB Pro 1, MB Pro 2, OfficeRunner, SD Office, SD Office ML, SD Pro1, SD Pro1 ML, SD Pro2, SD Pro2 ML. 3.7V 200mAh Lithium-Polymer Rechargeable Battery Pack. 1 Year Replacement Warranty. MPF Products is a Registered Trademark.