This is a mount adapter for using EF lenses with GFX cameras. It's a very well-made adapter. Purchased new and used a few times, it's in overall excellent condition. Includes front and rear caps. Please be sure to test the functionality before confirming receipt. I will address any initial defects before you confirm receipt. Here's the manufacturer's description: The SHOTEN EF-FG01 is an electronic contact mount adapter developed for using Canon EF mount lenses with Fujifilm G mount medium format mirrorless cameras. The mount surface uses highly durable and rigid brass parts, providing high precision for attachment. It is equipped with a communication function (electronic contacts) and a function button that accesses the camera body, allowing for smooth operation of various settings and functions. When used with EF mount lenses without electronic contacts or in combination with EF mount conversion adapters, it supports image correction such as lens registration (up to 6 lenses), focal length setting, distortion aberration correction, color shading correction, and peripheral illumination correction on the camera side. This product was realized with technical support from TECHART. Ships within 24 hours. I do not have any pets, and I do not smoke. Please feel free to ask any questions. Please ask any questions or confirm details about the product before purchasing. I do not offer holds or exclusive listings.