I've perfected this simple yet effective tool for finding the center of any cylinder, now extending up to 30 cm / 23 inc in diameter. Thanks to the new ergonomic protrusion, it's more maneuverable and easier to grip during use. Additionally, I found it useful to add a longer ruler and a practical hole at the end so you can conveniently hang the tool.

It's recommended to reduce the first layer's speed and apply hairspray to the print bed to ensure good adhesion of lines and numbers.

To achieve two colors, you need to change the filament at layer number 3 and 3 layers before concluding the print.

Thanks also to the inspirational remix of my first model by @ jk_printer.
https://www.printables.com/model/1196365-improved-center-marker-with-ruler

Happy printing!