Alumina ceramic plungers, are formed by isostatic pressing or dry pressing technology. Grinding and polishing provide a uniform working surface for a stable performance. Through long operation, there is no leakage or just low leakage because of the high wear resistance of alumina ceramics. The alumina material complies with different drinking water regulations including certification for use up to 85° for German KTW, United Kingdom’s WRAS and French ACS, also for NSF for food safety.