The 57.904.2055.0 is a knife edge disconnect block (type WK 4/TKM/U) designed for safe disconnection and measurement in electrical circuits mounted on DIN rail systems. It features screw terminals accommodating fine stranded wire from 0.5–4 mm² or solid wire from 0.5–6 mm² (AWG 22–10), with a width of 6 mm and wire strip length of 9 mm. The block is rated for 800 V/8 kV/3 (impulse voltage) with a 600 V UL/CSA field and factory wiring rating, and carries a maximum current of 20 A. It complies with EN 60 947-7-1/DIN VDE 0611 T1 standards and is suitable for thermocouple measurement circuits, control systems, and general electrical interconnection applications requiring safe disconnection capability.