Black Aluminum Screw on Spike for Helmets Rat Rods Helmet Spikes Half Shell Harley Davidson 2 3/4 Inch Metal Spike This Black plated screw-on spike is perfect for creating a helmet that stands out in a crowd. You won't get lost in a sea of black helmets when you screw one or more of these sick puppies on your helmet. Also use them to add some wickedness to your bike, rat rod, car truck and anywhere else. COMES WITH THE screw has 1/4"-20 threads which are very common. These will fit the threads that hold the air cleaner on older cars that aren't metric. (great for rat rods) Beautiful polished black spike is 2 3/4" long. - Base of the spike is 3/4" dia. Meets or exceeds DOT requirements FMVSS 218 Shubandit Co. ships very fast via usps mail in a strong envelope 2-4 day US mail with tracking - Brand new USA made full Weather proof Made from solid aluminum, has a quality finish unlike the cheaper spikes available elsewhere.