Introducing the ZS Cold Rolling 4140 Hard Chrome Plated Piston Polished Steel Rod—engineered for durability and high-tensile strength. Crafted from 20CrMo alloy steel, these rods provide exceptional reliability with a smooth surface for optimal efficiency. Available in various diameters and lengths, they comply with API Spec 11B standards. Customize your polished rod for specific applications. Welcome to visit our website!