The Box Two Zinc Extended Performance Treatment (XPT) Chain takes Prime 9 durability a step further with a zinc-based treatment that delivers up to 14 times greater corrosion resistance than standard nickel plating—ideal for wet, muddy, or high-salt conditions. Like all Prime 9 chains, it features chamfered shifting edges, solid plates, and solid pins for long-lasting strength, along with our unique inner link spacing designed to pair perfectly with wide/narrow chainrings. This variant makes the trusted simplicity of 9-speed even tougher, extending the life of your drivetrain without adding complexity. SUPPORT MATERIAL Prime 9 Technology™ View Prime 9 Drivetrain Compatibility Manual How is the Ebike variant different? View Prime 9 Comparison Chart View Prime 9 E-Bike Comparison Chart Why Prime 9?