This is a desktop electromagnet, also called a desktop electromagnet. It is characterized by small, easy-to-use, flexible, portable, high sensitivity and magnetic field stability. It is a cost-effective research-grade desktop electromagnet that brings convenience to scientific researchers. It is especially popular in the fields of chemistry, environment, materials and life sciences, such as free radical reaction mechanism, chemical reaction kinetics, advanced wastewater oxidation technology, persistent organic free radicals in solid waste, Feton reaction, SOD enzyme reaction, polymerization reaction, Oxygen vacancies, material defects, doping, reactive oxygen species (ROS), NO radicals, etc.