This is a Roomba Dual Mode Virtual Wall. I purchased it as a set when I bought the main unit, but I have never used it. It's a product that costs 8,250 yen (tax included) on the iRobot official website. However, there are some white scratch-like marks on the top (photos 1 and 2) due to something rubbing against it while it was left unused, so please be aware of that. There are absolutely no problems with its operation. I will also send test AA batteries along with it.