Tripolar head: For use on the eyes or face, recommended duration: 30 minutes; Quadpolar head: For use on the face/shoulders/arms, recommended duration: 30 minutes; Negative pressure head: For use on the shoulders, neck, arms, and legs, recommended duration: 5-10 minutes, until the sha effect is achieved. Fat-burning head recommended duration: 30 minutes. Note: While the negative pressure head can produce sha, it is recommended to wait at least one week for the affected area to heal before using it again. There are no specific requirements for other probes, but for optimal results, it is recommended to use them 3-4 times a week.