This collection of rings is ready for 3D printing.Ring sizes 16 16.5 17 17.5 18 18.5 19 19.5 20 20.5 21 mm. Approximate weight of rings by size(GOLD 14K): 16mm-6.66g 16.5mm-6.84g 17mm-7.02g 17.5mm-7.2g 18mm-7.38g 18.5mm-7.56g 19mm-7.74g 19.5mm-7.92g 20mm-8.11g 20.5mm-8.29 21mm-8.47g.