tapping screw is 7173 iso 1481 st 4 2x13c to specn no is 7173 89 warranty period 3 0 months after the date of delivery quantity tolerance 5 age item category normal total po value variation permitted max 8 lacs tapping screw is 7173 iso 1481 st 4 2x13c to specn no is 7173 89 warranty period 3 0 months after the date of delivery quantity tolerance 5 age item category normal total po value variation permitted max 8 lacs tapping screw is 7173