The HollowPin construction provides smooth, precise shifting and weight savings without sacrificing strength. Plus, it's the only 5.9mm chain with a secure, toolless attachment device that you'll find in cycling today. HollowPin contruction alows for uncompromised performance, strength, and light weight Compatibility extends to industrystandard 10 speed systems Easytouse toolless connection is reliable and unique to SRAM PowerLock connecting link PC 1070 Compatible Gears