The Nockturnal FIT Universal Nock System is designed for versatility and reliability. This strobing red/green lighted nock system is perfect for archers who want a consistent and accurate shot every time. The super strong clear Polycarbonate material ensures durability and long-lasting performance. With the included adapter sleeves, this nock can fit various arrow shaft sizes, including X, H, S, and GT nocks. Whether you're a seasoned pro or just starting out, this system is easy to install and provides a clear visual indication of your shot. Fast shipping ensures you'll be on target in no time.Key Benefits and Features: Material: Super strong clear Polycarbonate Nock size compatibility: X, H, S, GT