Spanner nuts are used for security when future removal is anticipated. Installation and removal require a special spanner nut driver. Made of a Non-Ferrous Rust-Resistant Zinc Alloy.
Hex nut breaks away when nut is tightened leaving only the tamper-resistant conical portion remaining. No special tool is required: Uses standard wrench for installation. These anti-theft security nuts should be considered non-removable. Aluminum.