Tri Groove security nuts feature a tapered diameter, making the nuts resistant to gripping devices. Security nuts 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 also referred to as T Groove, Trident Drive and Coned Trident Drive Nuts.
Tri Groove Security Nuts are made of Zamak 5 Zinc Alloy (95% Zinc, 4% Aluminum, 1% Copper). Zamak is an alloy of Zinc and Aluminium, sometimes also incorporating Magnesium and Copper. The added copper in Zamak 5 increases the strength, hardness, and corrosion resistance of the alloy, but reduces its ductility and dimensional accuracy compared to other Zamak Alloys.