The 1SNA178646R1100 is a FEM3A series blue end section, designed to provide a safe and finished termination for a row of M 4/6.3A terminal blocks on a DIN rail. With a slim profile of just 3 mm, it securely snaps onto the open side of the last block in an assembly. This covers the exposed metal components, preventing accidental contact and maintaining the overall insulation integrity of the circuit. It is an essential accessory for building compliant and professional control panels using the 4 mm² SNA series terminal blocks.