Sennheiser XSW-D Portable Lavalier Set. Includes: Transmitter and receiver units ME2-II lavalier microphone USB-A to C cable Belt pack clip 3.5mm coiled cable Hot shoe mount Separation stickers The wireless system units have been used to a certain extent, so they are not in pristine condition. The lavalier microphone is unused and in excellent condition. The battery usage is unknown, but it does light up green, so I think it has at least 75% remaining. I used it with an ME3 headset, and the wireless delay is only 4ms, making it easy to use. It's one of the lowest latency wireless systems in this price range. The sound quality depends on the microphone quality, but it was excellent in an environment using the ME3 headset. I haven't used the ME2 lavalier microphone since it's unused, but I expect it to be compatible. It's convenient that you can set the mute from either the transmitter or receiver, and the LED indicates the mute status (I use Wireless Pro, and it's very inconvenient that this isn't possible). The problem is that in crowded environments, it seems to be affected by Bluetooth, etc., and the sound sometimes cuts out. It can be resolved by using an extension cable to get as close as possible, but it's a bit of a hassle (personally, this is why I stopped using it). Also, the remaining battery indicator is difficult to understand (green light for 75% or more, yellow for 5-75%, and red for 5% or less, which is really confusing). By the way, it's not recommended to use it while charging, as it causes noise. It's perfect if you want to use it with clear sound at a not-too-distant distance.