The core functions are different, the higher the version, the more complete the functions. The frequency difference of HIFU/RF projection and the depth range of action are different, the higher the version, the better. At the same time, 4.0 can be used for all, and the rest are suitable for face. 

Yes, this device is suitable for tightening and lifting most areas of the face and neck. However, it is not recommended to use directly around the eyes or eyelids, as doing so may harm the delicate eye area. We strongly recommend avoiding this area. If you need guidance on safe application areas, please let me know! 

It is not mainly used for weight loss, but for non-invasive beauty purposes such as skin tightening, contour lifting, and wrinkle improvement. However, it can indeed have a mild fat reduction effect in some cases, but it is different from the real "weight loss". 

Avoid using it on skin with wounds and inflammation. It is okay for acne scars, but not for acne. Avoid using it during acne.