Security washer for security paneling system

A security washer for use with a removable security fastener to tamper-resistant secure a first member to a second member, the security fastener having a shank connected to a slotless head having a peripheral edge portion with a height and a smooth, generally oblong peripheral shape and being rotatable for installation and removal with a special driving tool, the tool having a driver head including an outer periphery having a maximum outside dimension and a cavity having an internal shape corresponding to the shape of the peripheral edge portion of the security fastener head and being adapted to fit over and drivingly engage the peripheral edge portion, said security washer comprising:

• a body having a circular outer periphery, a smooth, generally convex outer surface and a central aperture through which the shank of the security fastener extends;
• and
• a recess in said body and concentric with said aperture for receiving the head of the security fastener, said recess having a bottom wall on which the peripheral edge portion the security fastener rests, a depth at least about as deep as the height of the peripheral edge portion, and a minimum inside dimension approximating but slightly greater than the maximum outside dimension of the tool driver head to permit the cavity of the tool to fit over the head of the security fastener and drivingly engage the peripheral edge portion thereof for rotating the security fastener, thereby minimizing access to the head of the security fastener with a tool other than the special driving tool.