Obsidian DIY Mouse Skates – Universal 0.8mm PTFE Dots with diameter 6.5mm, offer better control and stop. which surface is hard and finely frosted texture, effectively increasing the friction of the surface, especially hardened PTFE increases the braking power of the skates, allowing better control and emergency stop. Which is suitable for cloth mouse pads & glass mouse pads, Not for Coating or plastic mouse pads.   How to install universal dots skates? please refer to the layout reference. DIY Tip:Fewer dots provide greater speed. Conversely, more dots slow down. Package Included: 40 dots skates Two alcohol Pads Two adhesive remover wipes