Sennheiser HSL10 II, lets you remotely answer and end a desktop phone call.  Compatible with all Sennheiser wireless headsets (including discontinued models).  The HSL10-II is connected to the Sennheiser wireless headset base, which is in touch with your wireless headset. By answering or ending the call on your wireless system, 
 
Compatile with all Sennheiser wireless headset models: SDW 5066, SDW 5065, SDW 5036, SDW 5035, SDW 5015, SDW 5016 DW Office, DW Office ML, DW Office Phone, DW Pro 1, DW Pro 1 ML, DW Pro 1 Phone, DW Pro 2, DW Pro 2 ML, DW Pro 2 Phone, SD Office, SD Office ML, SD Pro 1, SD Pro 1 ML, SD Pro 2, SD Pro 2 ML and D 10 Phone.
 
Key Features:

• HSL10 with mounting strips and extender arm
• included kit allows onnection to different phone styles
• Height adjustment for customization to phone handset
• Ring detection mic can be repositioned for customization to phone make/model
• Replace HSL 10 (500712)
• 1000756 

For more information.  See Sennheiser HSL10 II datasheet, Sennheiser HSL10 II user manual