Black Neoprene Protective Slip-On Knee Pads - Your Purchase Includes Two Knee Pads. 2mm Neoprene On Back Side. Close-Cell Foam Cold Molded Padding In Knee Protection Area. The Knee Pads Just Slip On And Attach To Your Knees To Your Specific Needs. One Size Fits All.California Proposition 65 WARNING: This product contains a chemical known to the State of California to cause cancer, birth defects and other reproductive harm.