Single Flare > 10 gauge ~ 2.5mm > 6 gauge ~ 4mm > 1 gauge ~ 7mm > 0 gauge ~ 8mm > 00 gauge ~ 9.5mm > 1-1/4 inch ~ 32mm > 1-3/8 inch ~ 35mm > 1-1/2 inch ~ 38mm > 1-7/8 inch ~ 48mm > 2 inches ~ 51mm