This keyboard was gathering dust in the warehouse. *I check its functionality about once every few years.* It has hardly been used. I mainly used other mechanical keyboards and laptop keyboards. Also, there is no tobacco or pet odor. Box and accessories are included. I will post images as soon as possible. Original purchase price was probably around 25,800 yen. ---Overview--- It worked without any problems on a Windows 10 PC, but I couldn't use it on a new PC I bought to match Windows 11. *It seems that not all Windows 11 PCs will have the same problem.* To be precise, it cannot be used without certain settings. It doesn't seem to be completely unusable. Below is the reply from the manufacturer: --- This is the REALFORCE Customer Center. . Regarding the "SE1800," it is not a supported model for Windows 11. Therefore, problems may occur depending on the environment. Also, since this product has already ended its maintenance support, we do not offer support such as updating to compatible firmware. *Also, they have stopped accepting repairs.* --- I believe this problem applied to my situation. While searching for solutions, I found a Hatena Blog by "Piccy's Memo" and was able to use it after following the steps below. *However, the same settings are required every time it is started.* → When connected to a USB port, all the lights flash for a moment, but then turn off and it is not recognized. I thought the USB 3.0 port was the problem, so I switched to a USB 2.0 port, but it didn't change, and the same thing happened even after restarting. When I opened Device Manager, a "USB Input Device" with a warning mark was displayed under "Human Interface Devices." I disabled the device with the warning mark and then re-enabled it using the following steps: 1. Open Device Manager, right-click on the "USB Input Device" with the warning mark, and click "Disable device." 2. A confirmation screen will appear, so click "Yes." 3. Right-click on the disabled USB Input Device and click "Enable device." Below is an overview of the product --- *Quoted from the official HP.* Realforce 87UB Discontinued