Hinge Type: Double Action / Spring Hinge (Allows doors to swing smoothly in both directions and automatically returns them to the center closed position).Brand/Series: NR Hardware Hinge Series (NAN-RONG).Model Number: B4-2.Size: 100mm (4 inches).Material/Finish: Chrome Plated (CP) Steel or Stainless Steel.Common Applications: Frequently used for heavy-duty swing doors, such as café or salon doors, counter gates, and bar doors.