Ball marker set: Simple Good mark, black and red, set of two. Diameter: 22mm, Thickness: Approximately 3mm Suitable for the size recommended by the association for ground golf. Attaches to magnets. Magnets are not built-in, so please use a base such as a clip with a magnet. It shines and sparkles under the sunlight, making it easy to find, and is perfect for various types of golf. These are handmade by me using resin. The inside is steel, and the back is finished with stainless steel foil. How about a small gift for family and friends who enjoy various types of golf? I also have 25mm markers and other handmade markers with different designs for sale, so please take a look. These are handmade by an amateur, so there may be some imperfections, but please understand.