The 4 channel hotplate magnetic stirrers are designed for parallel experiment and multiple parameter optimization, thus can serve as handy tools for Kjeldahl nitrogen determination, Soxhlet extraction and parallel synthesis, etc. They are ideal choices for test laboratories in food, animal feed, textile, soil, sewage, water treatment, polymerization, petroleum products, resin and plastic sectors. The user can handle 4 tests at the same time with stable performance, good reproducibility, high accuracy and easy operation.