沉头机螺钉 Flat head machine screws
内六角平端紧定螺钉 Hexa..
半圆头内六角螺钉 Hexag..
沉头内六角螺钉 Hexago..
内六角螺栓 Hexagon ..
外六角全牙螺栓 Hexago..
沉头机螺钉 Flat hea..