Sony MDRXB450AP Extra Bass Smartphone Headset (Black) Acoustic Bass Booster for incredible bass response, 30mm drivers for wide frequency response (5 - 22 kHz), In-line microphone for hands-free phone calling and volume control. Connectivity Technology: Wired Compatible with Apple or Android smartphones, Free SmartKey App for customized in-line remote function Lightweight on-the-ear design, Swivel design for portability, 47 1/4 in. (1.2m) tangle-free Y-type cord