Plugs > 10 gauge ~ 2.5mm > 4 gauge ~ 5mm > 2 gauge ~ 6mm > 1 gauge ~ 7mm > 0 gauge ~ 8mm > 1/2 inch ~ 12.5mm > 1 inch ~ 25mm > 1-1/2 inch ~ 38mm > 1-5/8 inch ~ 41mm > 1-3/4 inch ~ 44.5mm