Plantronics M214C Headset with Adjustable Volume Headset easily plugs into cordless handsets and cell phones (requires 2.5 mm jack) Boom-style microphone with noise-canceling technology for enhanced sound clarity Lightweight, over-the-head design with adjustable headband for comfortable, secure fit Single-ear design lets you keep one ear on your household One-touch in-line volume and mute controls puts sound management within easy reach 3.5mm adapter required to use with iPhone (sold separately)