ELDORESO Bi-Color Twin Cap S size This is a slightly larger size, so it's recommended for those who usually wear a size M cap. Quoting from the following site: This is a running cap with a double-brim design, combining moisture-wicking and quick-drying nylon material with mesh material, with brims on both the front and back. The deep two-tone colors allow you to enjoy a different look depending on the direction you wear it. The surface is intentionally sewn to show some stitching, and combined with the color scheme, it has a classic appearance like a vintage item. When worn with the brims on both sides, it's a unique cap that can be enjoyed like a hat. The underside of one brim has a "MY BEAT" print, which adds an accent when the brim is flipped up. The adjuster belt is also placed in two locations, allowing for a wide range of size adjustments. Material: 100% nylon Separate fabric: 100% polyester