10mm Swingarm Slider Spools bobbins for Kawasaki Ninja ZX6r ZX10r ZX12r ZX14 Zx14r by GPI Industries - Not for 2013+ ZX6r (ZX6r 2013+ Uses 8mm) Each 10mm swingarm slider spool is precision CNC machined from High Impact DuPont Delrin Polymer resin Superior toughness and strength with reduced wear and friction during impact Lightweight yet strong and will not shatter or dig in when hitting pavement High grade steel mounting hardware. Each swingarm slider comes with a solid aluminum core for added strength Do not be fooled by cheaper, smaller spools that break off easily without aluminum cores and are made from plastic