1. Product Sub‑series / Structural Designation Difference: The “04” versus “02” in the part number, along with the “N4X” versus “N12” in the description, indicate that the contactors belong to different internal product sub‑series or mechanical platforms. Their core electrical parameters (coil, main contacts) are identical, allowing them to meet the same circuit control requirements. The main differences lie in mechanical outline dimensions, internal layout, and potential incompatibility with accessory mounting interfaces (e.g., auxiliary contact blocks, mechanical interlocks). In space‑constrained installations or when specific add‑on modules are required, verify the exact mounting dimensions and accessory part numbers. 2. Accessories and Expandability: As products from different sub‑series, their dedicated clip‑on auxiliary contact sets, timer modules, pneumatic timing heads, and other add‑on devices may not be interchangeable. If the original application (LCE04) uses certain Siemens accessories, replacing it with an LCE02 may require switching to the corresponding accessories designed for that sub‑series. For applications requiring only basic contactor functionality, this difference does not affect direct replacement.