The KEMP USA 10-424 Nickel-Plated Brass Pea Whistle is made durable plated brass for superior strength and performance. This whistle design incorporates a high-quality cork "pea" sphere inside the body to produce the familiar piercing, shrill attention-getting whistle tone. This whistle may be used indoors or out for safety by lifeguards, group leaders, swim coaches, and more.