These Forgefix high-low thread Concrete Frame Screws are Zinc Yellow Passivated for increased resistance to corrosion. They offer a virtually stress free fixing, allowing close to edge applications. They are through-fixing, eliminating the need for marking & re-positioning when fixing batons etc. The Torx head of the screw enables increased torque control. Supplied complete with cover caps & Torx bit. APPLICATION: Extremely popular fixing for window & door frames. Also now used as a versatile fixing for many applications in DIY, Joinery, Plumbing & Electrical trades. The Zinc Yellow Passivation process of electroplating is similar to the Galvanised & Zinc Plated processes but with the addition of a yellow dye. It offers an aesthetically pleasing finish, whilst having excellent resistance to corrosion. By design, TORX head screws resist cam-out much better than Phillips or Slotted screws. Where Phillips heads were designed to cause the driver to cam out, to prevent over-tightening, TORX heads were designed to prevent it & to achieve a desired torque consistently. TORX head sizes are described using the capital letter T, followed by a number. A smaller number corresponds to a smaller point-to-point dimension of the screw head. Only the proper driver can drive a specific head size without risk of ruining the driver or screw. High-Low Thread screws have an excellent holding power in wood due to their alternating high & low thread heights. Concrete Frame Screw Torx High-Low Thread ZYP 7.5 x 132mm Box 100