Cordless Telephone System

At my work we have Uniden cordless phones with two incoming lines. I'm looking for a wireless headset that will be compatible with a multi-line. I want a helmet that fits over the head. Suggestions? How do I know when they are to investigate whether a landline or wireless phone?

This work with:
http://www.cordlessworkz.com/index.asp?PageAction=VIEWPROD&ProdID=2060
http://www.cordlessworkz.com/index.asp?PageAction=VIEWPROD&ProdID=1335

This model only works w / cordless phones:
http://www.cordlessworkz.com/index.asp?PageAction=VIEWPROD&ProdID=1336