Syba NC-2 Headphone with Built-In Amplifier and In-Line Microphone, Black (OG-AUD63053) Internal headphone ampifitler helps power the dual driver, 30mm and 40mm driver, within the headset. Controls for both Volume and Bass level. Driver Impedance: 30mm 32 and 40mm 32 Gold Plated 3.5mm Jack 4-pole Connector (Compatible with Smartphones, and Tablets) Cable Length of 62" with Twin 3.5mm 45" Cable Adapter for PC and Laptops is included