This five-electrode cell, model C004 from Tianjin Aida, is developed for electrochemical testing of small reagent volumes, with a working capacity of 5 to 20 ml. Designed as a versatile electrolytic cell, it allows custom configuration of working, auxiliary, and reference electrodes—all supplied in extended-length variants for compatibility with standard setups. Optional accessories such as a Luggin capillary and gas inlet/outlet tubes further support controlled measurements. The cell is suited for experimental materials research, energy material evaluation, and analytical electrode studies where minimal sample volume and modular electrode choices are critical. It does not include electrodes; those shown in photographs are for reference only. This product provides a flexible platform for electrochemists needing a compact, adaptable testing environment.