... Made, with plastic head;Overall length: 26.82mm, effective length: 4mm, Diameter: 1.29mm;N2-MK,Korea Made, all steel needle;Overall ... length: 26.72mm, effective length: 4.5mm, Diameter: 1.16mm; N2-MK is with longer longevity always as ... Microtach Pin we offer is from 3.5mm to 5.4mm, and 4.5mm & 5.4mm are our normal sizes.