This was given to me, but the outer bag doesn't have the size written on it. Comparing it to my son's Apple Watch (see the 4th photo), I think it's around 42mm. I'm not familiar with Apple Watches, so if you know about them, please purchase this. Compatible sizes: 42/44/45/49mm Type: Third-party product ⭐Anonymous delivery & Free shipping⭐ Please check the actual photos for the product condition♪ #Yumin♥️ Click here for a list of products with no comments & immediate purchase OK❣️✨☜ ------------------------------------ * I opened it once for inspection, so it's listed as "Like new," but the product is unused! * Please note that the actual product may differ from the image photos, so be sure to check the actual photos! * Other notes... Please read the profile! 1-46 956