The Spikes are all metal and have a specialnickel plating that wont corrode or tarnish over time! The 10-32X1/4 inch threaded stud is stainless steel and has an allen socket in the end for easy tightening without damaging the spike.

 The kit contains 4 spikes with studs, nuts, lock washers, and rubber O rings which help prevent loosening due to vibration.

 The spikesare 1/2 iinch in diameter at the base and 3/4 inch tall.

Suggested retail price~ $12.99 for the set of four!