In-ear earphones. Features: Single Dynamic Driver produces great sound in a convenient and portable package. Sound Isolating design blocks up to 37 dB of outside noise for immersive listening no matter where you are. Wired 3.5 mm option includes velvet drawstring case and fit kit with three sizes of soft flex sleeves. Sensitivity: 105 dB SPL/mW. Frequency Range: 25Hz – 17kHz. Impedance: 16 Ω.