Headset -Telephone headset connector Highlights generic brand Telephone headset connector Description: Universal RJ9 to 2.5 or 3.5 mm headset cable adapter. With this adapter or converter, you will be able to use your own favorite headset or stereo headset with a 2.5mm OR 3.5mm jack with your hands-free phone. This adapter converts the standard 2.5mm or 3.5mm phone headset jack to a standard RJ9 jack, for the phone or handset headset jack, you will be able to make and receive phone calls through this adapter with your own headset or stereo headset preferred of any type or brand with a 2.5mm or 3.5mm male plug. It's convenient to have one headset and be able to use it with your own phone and your Cisco phone in the office or anywhere. Easy installation, simply insert the RJ plug directly into your telephone headset or handset port, will not require any additional amplifier, and insert your own favorite headset with a 2.5mm or 3.5mm plug into the other end of adapter, and you are ready to make or receive hands-free phone calls. specification: Material: rubber surface and metal core Size: 40cm Package includes: 1 x RJ9 to 3.5mm cable (2-pack) 2 x 3.5mm to 2.5mm adapter (2-pack) Note: It is manual measurement, there may be 1-3mm error. And item color displayed in photos may be showing slightly different on your computer monitor since monitors are not calibrated same. I hope to understand. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.