Premium gold series motocross chain. The PT520 MX was designed to handle the increasing horsepower demands of today's 4-Stroke motorcycles; all components of the chain use a ProTaper exclusive heat-treating process to aid in the life of and durability of the chain. Designed for 125 to 530cc applications. Lightweight, ultra high-strength chromoly construction with 8,000 lbs. of tensile strength.