Tamper-Resistant Lock, 1-inch, Aluminum, White, Hex Screw Heavy-duty extruded Aluminum lock with tamper-resistant single hex security screw and wrench for use on metal horizontal sliding windows. Securely locks window in closed or ventilating position and helps prevent accidental opening of window by children. For a non-heavy-duty lock see item no. U-9980 or U-9982. For a non-marring lock see U-9820, U-9821 and U-10551. For vinyl windows use U-9809 or U-10547.