mine is 6 cm diameter inside, you can use the scale to fit your hand .
I used a lighter to smooth out any burrs after removing the brim.
My others designs
You shall not share, sub-license, sell, rent, host, transfer, or distribute in any way the digital or 3D printed versions of this object, nor any other derivative work of this object in its digital or physical format (including - but not limited to - remixes of this object, and hosting on other digital platforms). The objects may not be used without permission in any way whatsoever in which you charge money, or collect fees.