Polyester film backing for durability, flexibility and uniformity Micro-cut precision grains increase cut-speed and accuracy Advanced resin-over-resin design reduces shelling and increases performance and durability Proprietary anti-clog technology reduces paper loading and friction, as well as extends product life Patented SynWave Technology simultaneously sands flat and curved surfaces without gouging – reducing finish sanding up to 50% Smart-sized packs Warning: This product can expose you to chemicals which is [are] known to the State of California to cause cancer and birth defects or other reproductive harm.