Tornillos de cabeza hueca hexagonal de acero al carbono 12.9, negros, DIN912, métricos
DIN 912 (ISO4762) Hexagon socket bolts are also called cup-head hexagon socket bolts. The shape is cylindrical head and the groove is hexagon socket polygon. Hexagon socket head bolts are widely used in mechanical installation because they are easy to fasten and disassemble, and are not easy to slip.