This is the VILTROX NF-FX1 mount adapter. It's an adapter for mounting Nikon F-mount lenses on Fujifilm X-mount bodies. I used it a few times, then purchased one with AF functionality, so I haven't used this one and have been storing it. Because it has an aperture ring, you can use it with all kinds of F-mount lenses, including G-type lenses, which generally can't be used on mirrorless cameras. It also has a tripod mount, so you can use a tripod or monopod for stable shooting when using heavier lenses, reducing the risk of damage to the mirrorless body mount. Would this be suitable for those who frequently use FUJIFILM and Nikon?