These are original equipment SRAM replacement disc brake pads for Code and Guide RE 2011+ brakes. They have a steel or aluminum back plate and come in two compounds: organic and metallic. Organic pads have more initial bite and quieter braking. We'd recommend these for lighter riders and dry conditions, though it does come down to personal preference. For any wet weather riding, metallic pads are the preferred choice. Metallic pads also last longer and provide more consistent braking power on long descents, great for gravity trails and larger riders.