... metric unit(mm)1/4" x 1/4"6.4mm x 6.4mm22,23,243/8" x 3/8"10.6mm x 10.6mm19,20,21 ... ,21,22,235/8" x 5/8"16mm x 16mm18,19,20,21,3/4" x 3/4"19.1mm x 19.1mm16,17,18,19 ... .41mm,2.11mm,1.83mm,1.65mm2" x 4"50mm x 100mm2.11mm,2.5mm4" x 4"100mm x 100mm2.0mm,2.5mmTechnical Note:1,Standard ... ,17,18,19,20,213/4" x 3/4"19mm x 19mm16,17,18,19,20,211" x 1"25.4mm x 25.4mm15,16,17 ...