Self Drilling Screw, Stainless Steel Screw, Tek Screw manufacturer / supplier in China, offering Pan Head / Flat Head / Hex Washer Head Self Drilling Screw Self Drilling Tapping Screw Tek Screw, Alloy Steel / Steel Thread Rod Stud Bolt Thread Bolt B7 B7m, High Strength Heavy Hex Bolt Tc Bolt (Tension Control Bolt) for Steel Structure and so on.