If you want to see my best projects, I invite you here: 

https://cults3d.com/en/users/Guliwer06/3d-models

Summary

Inner diameter = 6cm
Rectangle = 2.3cm X 6.3cm

Print Settings

Printer Brand: 

Creality

Printer:                      

Ender-3 S1

Rafts: 

Doesn't Matter

Supports:                      

No

Resolution: 

0.2

Infill:                      

100%

Filament:

Colorfil PLA                Black