1. Coil Termination Method: Documentation indicates that the -CU variant uses a “BUSBAR” connection, while the -CL variant employs “WIRE LEADS.” The -CU’s coil is designed to be powered via a fixed copper busbar or rigid terminal block integrated into the relay body. This configuration is typically used in fixed installations demanding low connection impedance and high reliability. In contrast, the -CL utilizes flying leads for coil power, offering greater installation flexibility and facilitating on-site wiring, though it may necessitate additional cable management. 2. Price: The -CU is priced significantly higher than the -CL. This cost differential primarily reflects the structural complexity of the termination hardware, material costs (integrated busbar vs. wire and crimped terminals), and the associated installation suitability. For budget-sensitive projects where installation conditions permit, the -CL offers a cost advantage. In summary, if the system design can accommodate the change from a “rigid busbar” to a “flexible wire lead” for coil power (e.g., by providing sufficient wiring space and a reliable wire-securing method), the -CL can be used to replace the -CU to reduce cost. Conversely, if the original design strictly relies on a rigid busbar for connections in compact or high-vibration environments, substitution may introduce additional risks to installation reliability.