In-ear wireless sport headphones. TwistLock technology provides a secure fit, ensuring these headphones never fall out even during the most rigorous physical activities. FlexSoft Guaranteed never to hurt, these headphones are ergonomically designed to avoid nerve rich areas of the ear for long-lasting comfort. Made with ultra-soft medical-grade, flexible silicone to ensure a comfortable fit for hours on end. Developed for training in any conditions, the Inspire 500 endures through rain, water, and sweat. The sweat and water resistant 3-button microphone system to control phone calls and music tracks without breaking from your work-out. Compatible with most smart phones. 8-hour life smart battery with LED and audible indicators. Dynamic Driver size: 12.2mm, Frequency response: 20-20kHz, Impedance: 32 Ohm, BT type: 4.1, Battery Lifetime (hr): up to 8, Weight: 17.5g. Color: Black.