XB4 / ZB4 Series 22mm Metal Push Buttons Schneider Electric Components XB4 / ZB4 is a range of metal push buttons, switches, and pilot lights that combines the simplicity of installation, flexibility, and robustness to meet most industrial applications. Schneider XB4 / ZB4 delivers one of the most comprehensive product ranges available on the market and meets the robustness and performance requirements for the majority of industrial applications.