This item is slightly defective. EPOS SENNHEISER ADAPT series, Sennheiser Wired headphones/headset. It's been about six months since I stopped using it. I'm not sure if it's a problem with the jack connection or the microphone, but I tested the microphone 3-4 times, and the first time, my voice was muffled for the first 5 seconds. However, there was no problem if I continued to use it for more than 10 seconds. I couldn't reproduce the same symptom, and it worked normally from the second time onwards. The above points are the reasons for the defect. There is no box or instruction manual, so I'm not sure if it's ADAPT 160 or ADAPT 165, so please judge from the images. To keep the price down, I will ship it in simple packaging.