The Volvik Pro Bismuth is a premium level 3-piece golf ball designed for advanced golfers with higher swing speeds The Pro Bismuth is favored by numerous international professional golfers Soft impact and feel and longer flight distance is achieved by World's First Patented Dual Core: a soft outer layer and a hard inner core 3-piece Tour Performance - Explosive distance and more accurate approach by Power Core, Bismuth Control layer and Zirconium Z-I Outer Cover Excellent putting feel and optimal spin rates made possible by more durable/softer Zirconium Z-I cover Improved flight stability designed 446-Octahedron dimple pattern 92 Compression, 64 Cover Hardness Optimal for 90-125 MPH Swing Speed