Spike strip #1041 Skull & Crossbones Motorcycle Helmet spikes. Approximately 17" long. Talk about an attitude adjustment!! Try on these killer helmet spikes. No drilling required. These spike strips come with two-sided industrial grade tape that becomes stronger with time. They are applied directly to the top of the helmet, just peel off and apply. Length is easily adjustable to your helmet with the use of scissors. All sales final due to the one-time application method. Helmet not included.