Fonus Black Retractable 3.5mm Mono Handsfree Headset Earphone Single Earbud with Microphone for Boost Mobile Samsung Transform Ultra, Boost Mobile ZTE Force, Boost Mobile ZTE MAX, Boost Mobile ZTE Warp 4G FONUS(TM) Brand Premium Retractable Mono Handsfree Headset with Microphone. Premium sound and voice quality. Allows user to talk and listen to music hands free. Retractable cable is compact and can be stored on. Tangle free design. In-line microphone in ABS housing. Adopted a highly conductive gold plated 3.5mm plug. Excellent Bass Response. Works on any device that have a 3.5mm port. This is a MONO headset with ONE Earbud only. NOTE: Please pull the retractable cords on both sides simultaneously for a better result.