Phase 5's ar-15 pistol buffer tube foam pad is made from npvc (also known as nbr or nitrile), a durable material with good abrasion resistance and high tensile strength.The foam is resistant to oils and fuels, as well as the destructive effects of ozone and uv light.It fits 1.25" diameter buffer tubes on ar-15 pistols.Finish: BlackType: Buffer Tube CoverModel: Buffer TubeDimensions: 3.50" LMaterial: Nitrile