you most probably will. most US devices dont support dual voltage and run on 110. india and the subcontinent uses 220.
as a solution you could buy a step down transformer for cheap from india. you could ask around in any electrical store. this will convert the voltage to 110 and allow you to operate the phone. keep in mind though that all 4 headsets use 4 independant power sources. if you plan to use them in 4 seperate areas you're going to need 110v for all 4.
hope this helps

This product does not have world wide voltage 100v - 240v. The adapters are suitable to work at 110v