XF6-40 pressure to rotary-round sub-line boxes, for main city telephone cables to the main line, and applicable to farmers so that overhead lines can be installed. Features: XF6-40 series product line introduction boards have trapped gas tight rotary cards. Adopting top-line users to attack screw pressure, reliability and oxidation resistance are ensured. Each piece connects to the line of acetate fiber and is equipped with fuses, so that if communication lines are struck by lightning or strong currents, the related communications equipment will be protected. Box housings are made from quality cold-rolled steel, with the surfaces being electrostatic coated to reliably meet the GB4208 protective performance standards.