Everyone in the office could use more flexibility. Let them roam confidently up to 400 ft from the headset base. Theyíll be able to collaborate simply since teams can conference up to four headsets on a single base. Thereís more than one way to make a call ó switch up styles to find your groove and introduce your ears to something new. The CS540 convertible design comes with three wearing options: over-the-ear, over-the-head, behind-the-head .