Please note that the built-in spring may require more frequent replacement depending on usage intensity and the level of strain applied—particularly how far the spring is stretched during operation. Over time, the plastic material of the spring can deform, reducing its ability to store and release energy effectively. To replace the spring, follow steps 10 to 14 of the manual in reverse order.

Additionally, please ensure that the drive wheels are fitted with a rubber coating. Without sufficient grip, the wheels may slip at high frequencies and fail to efficiently transfer energy.

I recommend regularly inspecting both the spring and the drive wheels to ensure optimal performance and reliability.