Canon Extender EF 2X III (3rd Generation 2x EF Extender) MEIKE Extension Tube (Bonus) I purchased this used and have owned and used it for over 5 years. While there is a feeling of use on the exterior and mount, there are no noticeable stains on the lens as far as I can see. The operation was also confirmed as follows: EOS R50V → MEIKE EF-RF Mount Adapter → "Extender EF 2X III" → Sigma 100-400 F5-6.3 DG OS HSM The F-number display also shows approximately 2x, and I did not feel any problems with the screen condition, connection status, or shooting. The MEIKE extension tube was purchased a long time ago for simple macro photography. It only extends the electronic contacts, so I think it will work, but it's just a bonus. Included items: Extender body Front and rear caps Pouch Packaging box Extension tube (EF, with box) Only these items are included. I have confirmed the operation and condition as much as possible, and I don't feel any particular problems, but as it is an electrical product, and from the perspective of preventing substitution, it is sold as-is, with no claims and no returns accepted.