... : concrete screw 2)Material: C1022, case hardened, surface hardness HV450-750, core hardness HV27 Window Frame Screw1) Application: it is for the ... into a wide rang of materials since they are suitable for concrete, solid re brick, hollow, blocks, natural stone, etc.2) Head ... , 132mm, 152mm, 182mm, 202mm, 212mm 4) Coating: Zinc, Yellow Zinc Concrete Window Frame Screw