1. Material: Made of low-carbon steel or high-permeability soft magnetic steel (such as pure iron, DT4, 1010/1020 steel), possessing good magnetic permeability and low coercivity. 2. Shape and Structure: The overall structure is cylindrical with a flat cut edge on the outer side (anti-rotation design), and a stepped concave structure at the top. 3. Size Range: Outer diameter is typically within the range of Φ10–Φ50 mm, and height 10–40 mm can be customized; internal hole diameter and step dimensions are precisely matched according to relay specifications, and OEM customization is supported. 4. Internal Design: The inner hole adopts a multi-stage stepped design + center thread/locating hole design to effectively control the air gap and improve magnetic flux density. 5. Surface Treatment: The outer surface is precision machined with a delicate brushed metal texture; zinc plating, nickel plating, or blackening treatments are available to improve corrosion resistance and environmental adaptability. 6. Manufacturing process: CNC precision turning is adopted, and the tolerance of key dimensions can be controlled within ±0.001mm; key contact surfaces are precision machined or ground to ensure coaxiality and magnetic performance consistency.