Client is "upgrading"

from her Nortel 3x8 to an XBlue next Tuesday. Just realized today that the X16's phones don't use standard headsets that use a modular connection, but need the type with a 3/32" plug.
Client wants (& uses) a model that is monaural & goes over the head.
I just checked Plantronics website & I don't anything available.
What do you use and/or recommend?