M8 Shear Nut Galvanised Mild Steel (Permacone - snapoff - Security - Tamper Proof) Shear nuts are also known as breakaway nuts, inviolable nuts, snap off nuts, security nuts, tamper proof nuts or permacone nuts. They are a permanent security solution ideal where maintenance is not required. They are designed to prevent unauthorised tampering or removal of equipment and facilities. They are typically used in public areas (schools, hospitals etc) and within the fencing industry, e.g. for security perimeter fencing. Tightened using standard spanner or socket Breakaway nuts - how they work: The hexagon nut section is fully tightened with a standard spanner until the pressure applied exceeds the maximum torque limit, which causes the hexagonal part of the nut to break off. This leaves a plain tamper resistant cone shape which is extremely difficult to remove as there is nothing to grip. Since hot-dip galvanizing typically adds 2.2 to 5 mils of thickness to the threaded portion of a