The Avid Elixir disc brake pads have a steel backing and come in two options: Organic or Metallic. Organic pads are softer and will provide more quiet braking and increased modulation. Metallic pads will offer longer life and improved heat dissipation. We always recommend Metallic for riders who often ride in wet conditions. The Avid Elixir disc brake pads are sold as one pair of left and right to fit one caliper and include the retraction spring.