A swimmer's accessory is a TOWEL. Towels are essential for swimmers as they help to dry off after swimming and can also be used to wrap up in between dives or laps. Towels are also useful for wiping away sweat and water from the face and body. They are usually made of absorbent materials such as cotton, terry cloth, or microfiber. Towels come in a variety of sizes and colors, making them a versatile and practical accessory for swimmers.