Single Flare > 6 gauge ~ 4mm > 2 gauge ~ 6mm > 1 gauge ~ 7mm > 00 gauge ~ 9.5mm > 11/16 inch ~ 18mm > 3/4 inch ~ 19mm > 1-1/4 inch ~ 32mm > 1-1/2 inch ~ 38mm > 1-3/4 inch ~ 44.5mm