Channel24 Head Glans Ring approximate measurementsMedium: 21mmLarge: 23mmPlease see image and note that gold weld has been used on balls. Get your shop listed now!!! This product is certified 100% Non-Magnate and medical-grade steel. Beware of cheaper products that are not solid surgical steel but chromed steel or poor quality surgical steel that contains Magnate. Magnate is the ingredient that makes steel rust. We will only include this endorsement on our 100% surgical steel products.