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-6.57g 16.5mm-6.79g 17mm-7g 17.5mm-7.22g 18mm-7.43g 18.5mm-7.65g 19mm-7.87g 19.5mm-8.08g 20mm-8.29g 20.5mm-8.51g 21mm-8.72g