6mm Swingarm Spools for Yamaha YZF R1 R6 R6s R3 FZ1 FZ9 FZ09 FZ10-6 mm Swing arm Slider Spools by GPI Industries Each 6mm 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