NoiZfree Music & Mobile Hands-Free Listening Double Earhook NoiZfree Double Earhook, 2.5mm Jack, 2.5mm to 3.5mm Jack Convertor 1 year manufacturer warranty Small, lightweight (10g) and easy to use unit For phone usage when hands are tied up, Comes with 2.5mm to 3.5mm jack convertor for use with not only cell phones but audio devices as well