Blow out sale item: This means we are getting rid of this item. It is not returnable or exchangeable. This item does not work with current or popular models, or does not sell well enough to justify storage. Delrin Spurs are precision machined from tempered plastic for unequaled strength and durability DELRIN MAIN GEAR(71T) Comes with only one gear Delrin® bridges the gap between metals and ordinary plastics with a unique combination of strength, stiffness, hardness, dimensional stability, toughness, fatigue resistance, solvent and fuel resistance, abrasion resistance, low wear and low friction.