This is from the SONY FE 600mm F4 GM lens. I'm selling it because I changed camera models and no longer need it. It's a genuine accessory, but not generally available, so if you need one, please take this opportunity to get it. It's an ultra-rare item. Additionally, I'm including a SmallRig anchor link, which makes it easy to remove when used with a 600mm F4 class lens, making shooting much easier and more convenient.