Tinksky 3.5mm Bicycle Motorcycle Motorbike Helmet MP3 Speaker Headphone with Volume (Black) Color: Black.Material: Mainly plastic. nterface type: 3.5mm connector.Total cable length: 186cm. With volume controller, making it easy to operate. Compatible with other devices such as MP3, phones etc with 3.5mm interface. Can be stuck to the helmet by velcro tapes.