FL's patented technology is that when the probe is against the skin, the instrument automatically detects the skin and emits energy, and stops emitting energy immediately after leaving the skin, avoiding injuries to customers due to excessive heat energy when not close to the skin. SD spiral induction means that the gun head will only emit energy when it is sliding. As long as the probe stops, the energy will stop immediately, avoiding continuous energy emission at the same part, which may cause energy accumulation and burns to the skin.