... openingWire diameter(BWG)In inchIn metric unit (mm)1/4”X1/4”6.4mmX6.4mm22,23,24 3/8”X3/8 ... ”10.6mmX10.6mm19,20,21,221/2”X1/2”12.7mmX12.7mm16,17,18,19,20,21,22 ... ”X3/4”19.1mmX19.1mm16,17,18,19,20,211”X1/2”25.4mmX12.7mm16,17,18,19,20,211-1 ... /2”X1-1/2”38mmX38mm14,15,16,17,18,191”X2”25 ...