Metal Steel Ball Spring Box Used for Rolling Shutter Door

Metal Steel Ball Spring Box Used for Rolling Shutter Door. Custom OEM/ODM Service: Accepts customer samples or 3D drawings for custom production since 2007. Rust-Resistant Surface: Bright galvanized silvery surface ensures perfect resistance against rust. Durable Q235 Steel: Constructed from general Q235 steel plate for high quality and durability. Multiple Size Options: Available in exterior diameters 200-260mm and interior diameters 42-76mm. Strict Quality Control: Every process is checked by staff, and products are inspected before packing. Free Sample Available: Free samples provided for quality check; buyer pays express cost. Reliable After-Sales: Defective products can be returned and replaced without extra fee. Professional Manufacturer: Established in 1990s with 20,000m2 factory and 60+ employees.