Small inner diameter is 5/16” Medium inner diameter is 3/8" Large inner diameter is 7/16” 0g and 00g are 1/2" diametere onlyCircles$48.00PriceGauge*SelectSize*SelectMetal*SelectQuantity*Add to CartMost designs and sizes are available in: Stainless Steel (316LVM ASTM F-138) Brass (85% Copper/15% Zinc) Copper (straight up copper)