Sennheiser HD 630VB Headphone with Variable Bass and Call Control Closed-back around ear audiophile headphone featuring a collapsible design for maximum portability. Premium materials used throughout including aluminum ear cups, yokes and sliders for durability and reliability. Innovative rotary variable bass control for customizing low frequency response. Integrated controls on the ear cup for music and call control, selectable for iOS (Apple) and Android (Samsung Galaxy) devices. 2 year warranty when purchased from an authorized Sennheiser dealer.