The Phoenix Contact 0800019:0021 Zack Marker Strip ZB 5 is an essential component for efficient and error-free wiring in industrial automation systems. Designed for terminal blocks with a width of 5.2 mm, this white marker strip is longitudinally printed with ascending odd numbers from 21 to 39, ensuring clear identification and organization within control cabinets. Ideal for use in complex wiring setups, this marker strip enhances maintenance efficiency and reduces wiring errors. Compatible with Phoenix Contact's THERMOMARK technology, it offers customizable labeling solutions for diverse industrial applications.