100% compatible replacement battery for your Sennheiser Officerunner, DW Pro 1, DW Pro 2, SD Pro 1, SD Pro 2, SD Office, D10, D10-USB, MB Pro 1 and MB Pro 2 wireless headsets. When your Sennheiser wireless headset battery no longer holds a charge, this replacement battery will refresh your battery talk time back to new. On average your Sennheiser headset battery will last 1-2 years before a replacement is needed. Some customers have their Sennheiser headset battery 5+ years before a replacement is needed!