Sport headphones. Features: Fliphook flexible two-way design allows you to wear the headphones either in-ear or behind-the-ear. Thanks to TwistLock and FlexSoft technologies, these headphones are lightweight and ergonomically built to ensure secure fit and stability no matter the workout. Sweatproof. Hands-free calls. Specs: Driver Size: 8.2mm Dynamic Driver. Frequency Response: 20Hz - 20kHz. Colour: Line Green.