Probably best in coloured plastic, polished silver or gold plated brass.
Maybe even try Premium Silver ;-)
Inner diameter: 18.4 mm.
Feel free to ask for a different size, while specifying the inner diameter in mm. Tip: precisely measure a ring that fits you well, on the inside, left to right.
2.132 w x
2.298 d x
0.839 w x
0.905 d x