This is oil for NSK bearings. Normally, if you apply oil to an NSK bearing for a yo-yo, it will become a responsive yo-yo. However, if you use this oil and tool, you can apply the oil without making it responsive. Product Contents: ○ Oil (Different ingredients from silicone.) Of course, it is safe and uses ingredients also found in hand cream. ○ Tool You will use this tool to apply the oil.