This can slightly improve accuracy using a special friction pad. It's a second-generation version that I want to open source for everyone to use. If sold, please credit the author and provide the download link.

Furthermore, the primary purpose of this hop-up is not to increase range. It is not recommended to use grub screws in the grub screw holes. The main function of this item is to vent air. The third generation has improved this situation but is not yet open source as it's still under testing. Everyone is welcome to print one, play with it, and provide improvement suggestions! Thank you very much for your support!

Rather than commercializing it for a bit of pocket money, I prefer to open source it. I want more people to improve this item, make its price cheaper, and allow more people to buy it without feeling a pinch, just like buying a small bag of gel beads.