Tapered diameter resistant to gripping devicesDriven by three grooves on the outside of the nutThey are also known as Trident Drive Nuts, T-Groove Nuts, and Tri Groove NutsInstalled using a special tri groove socketZamak 5 Zinc AlloyCommonly used on boats, docks, piers and pools Tri Groove security nuts feature a tapered diameter, making the nuts resistant to gripping devices. They are installed using a special Tri Groove socket, which grips the indentations along the outside of the fastener to turn the nut along a thread. Tri Groove Nuts are commonly used with driver-less fasteners, such as carriage bolts or concrete anchors for a secure assembly. If the nut is not easily accessible, the fastener assembly will be harder to be tampered with. Security Nuts are commonly used in public outdoor applications including campsites, parks, playgrounds, benches, cars and roof top tents. Tri Groove Security Nuts Zamak 5 Zinc Alloy Tamper Proof Nuts in this selection are made of zamak 5 zinc alloy. Zamac Zinc Alloy, a metal made of Zinc, Aluminum, Magnesium and Copper. Zamac Zinc alloy is designed to be durable and retain its strength and hardness over time, which adds to the benefits of tamper proof fasteners since they are suitable for long lasting applications. Tamper Resistant Design Tri Groove Nuts are circular and tapered making them extremely resistant to gripping devices. They require a special socket to grip the three indentations along the side of the nut to be installed. Common Applications Because of their tamper resistant design, Tri Groove Nuts are commonly used in public applications including campsites, parks, playgrounds, benches, cars and roof top tents.