Conclusion
The NIU GO 21 fulfills the role of a secondary or backup phone with commendable simplicity. Its lightweight build, dual-SIM capacity, long battery life, and resilient design make it suitable for users who need reliability without the frills of modern smartphones. While it doesn't match the multimedia capabilities of contemporary devices, its focus on essentials—call, text, and basic storage—cements its place in the market for those seeking straightforward mobile communication. Though discontinued, the NIU GO 21 serves as an example of classic mobile design, emphasizing function and practicality.