Features: brand new and high quality Use PC Headset with most VOIP phones that have a RJ9 headset jack (Not for RJ11). Adapter cable with 3.5mm Headset jack to RJ9 Desk Phones Jack forCisco and more. Don'for t need to worry about the compatibility. 3 kinds of converters of different standard inside to fit most brand. Convert 3.5mm plugs to 4P4C RJ9/RJ10 headset plug, you can use your own headphone to chat on telephone with this cable. Made of ABS plastic, which is durable and reliable. Specifications: Material: ABS Color: Black Interface: 3.5mm TRRS (Female) rj-9 4P4C (Male) Length: Approx. 40 for cm/15.74 inches Note: 1.Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 1x Extension Cable