If you plan on making rings, you need to get a ring mandrel.
THIS METAL RING SIZER IS ALSO KNOWN AS A MANDREL AND CAN BE USED TO RESHAPE AND STRETCH RINGS AS WELL AS SIZE THEM. SOLID STEEL SIZES 1 - 15 WITH 1/4
Steel Ring Sizer/Mandrel with Sizes 1-15 SALE
AQUSYZE, guaranteed accurate US sizes. Case hardened, hard chromed , stainless steel ( Rockwell 15-16) DEEP laser engraved markings. Stainless Steel
JSP Stainless Steel Ring Mandrel
True Size Ring Mandrels — Otto Frei
Steel Ring Mandrel and Ring Finger Gauge Kit
PrecisionFit™ Steel Marked Ring Mandrel (UK Sizes A-Z 6)
Ring Mandrel Sizing Tool USA and European Ring Sizes Aluminum Grooved Finger Measuring Stick Measure Jewelers Sizer Sizes 1-15 and 41-76
Expanding Stainless Steel Ring Mandrel with Hex Allen Key - Heavy Duty Ring Shaper Tool for Ring Turning and Ring Making ( Ring Sizes 7.5-10.5 )
US Size 0-13 Copper Ring Mandrel ⋆ Keepsaker Supplies
Ring Mandrel Oblong 6.5x8.5 - 18x23
YIEPET Expanding Ring Mandrel-Ring Mandrel for Lathe,Ring Stretcher,Ring Sizes(7.5-10.5) Turning and Manufacturing Rings Making
69-174 EURO TOOL Stepped Ring Mandrel on Base - Rings & Things