Part number M3 M3.5 M4. Thread size M3 M3.5 M4. Size 400PCS-M3/M3.5/M4. Fastener type Self-Tapping Screw. Cross Head Countersunk Screws Design: The flat head screws design makes these stainless steel concrete screws suitable for use in enclosed areas where the head needs to be flush or below the surface.
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