The model was created using 3ds max 2015. Material was assigned in blender and rendered. There are blender, stl, fbx, 3dsmax files. The design belongs to me. Do not steal. I am not a jewelry designer. There may be errors in the measurements. Inner diameter is 17.5 mm
STL (Stereolithography, filesize: 3.75 MB), FBX (Autodesk FBX, filesize: 3.47 MB), BLEND (Blender, filesize: 1.96 MB), MAX (Autodesk 3ds Max, filesize: 2.63 MB)