RS PRO Bright Zinc Plated Pan Steel Tamper Proof Security Screw, M4 x 20mm Pan Head Tamperproof Pin 6-lobe recess, BZP Steel Tamperproof security screws incorporating a spigoted recess which virtually eliminates removal without use of the special matching tool TO ISO 965, Part 2, coarse series Made from low carbon mild steel, zinc plated and clear passivated
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