A handheld counter is an electronic device used in biology teaching to quickly count cells, microorganisms, or other small objects. It is usually equipped with a touch screen display that can manually input or automatically record the number of individuals observed. In biology teaching, handheld counters can help students conduct cell counting experiments under a microscope, learn how to estimate cell density in samples, and understand the dynamic changes in cell growth and reproduction. In addition, it can also be used to statistically analyze other data in experiments, such as the number of plant seeds, the number of eggs in insect egg masses, etc.