These really stabilize rotary rulers. You can choose the little round \"inside piece\" or the square outer piece. Tried the ones with \"sandpaper\" type backing, but they can scratch cabinets, fabric, etc. 

✔  Apply these little rings to the back of any ruler to increase safety and cutting accuracy by preventing slipping.

✔ Accurate - For straight, precise cuts, enhance your ruler by adding non-slip!

✔ Safe - Increases safety and cutting accuracy by preventing slipping.

✔  Easy - Simply stick to the back of any ruler.

✔ Convenient - Transparent for easy fabric visibility.

Specifications: 

- Outer diameter: 1.9 cm/ 0.75 inch 

- Inner diameter: 0.63 cm/ 0.24 inch 

- Thickness: 0.5 mm/ 0.02 inch 

- Material: silicone gel

- Color: semi-transparent 

- Quantity: 48 pieces adhesive rings, 48 pieces adhesive dots，2 Sheets，96pcs total