This is a variable ND filter mount adapter that I impulsively bought three months ago, anticipating the purchase of a Canon R5 mark II. However, I ended up buying a Nikon Z8 instead, so I never even attached it to a camera, rendering it useless. I was really looking forward to smooth exposure control during video shooting, but since I have nothing to attach it to, I don't know what it's actually like to use. Nikon doesn't have anything similar with a variable ND filter, and it was the last hurdle in my decision to switch to Nikon, but in the end, I reluctantly gave it up. Please refer to Amazon reviews and the Canon website for details. I have opened the box, but it is a genuine new item. However, I threw away the box because it was bulky during storage. I will ship it in bubble wrap and another box, so please be aware of that. I have opened the box, so I have lowered the price slightly, but I will not discount it more than necessary since it is unused. If you want one, it's a little cheaper than the official price, so please consider it.