一种用于铝制变幅杆和增幅杆的非导电镀层，用于改善外观并提高耐磨性。
增幅杆上采用各种颜色来标识增幅杆的标称增益。
A nonconductive plating used on aluminum horns and boosters for appearance and increased wear resistance.
Various colors are used on boosters to identify the nominal booster gain.