Windshield Repair Bridge Seal Set by American. We have brought back our black end seals. They last a bit longer than the white and in our view perform just a bit better. Our windshield repair seals are chemical resistant Viton. They are designed to resist the acrylic acid in windshield repair resin. They are custom-made to fit our windshield repair bridge piston and cylinder but also fit other injectors. For more information on this, you can call us anytime. Small orders are sometimes shipped 1st Class. If you need USPS Priority Mail there is no extra charge. Please write that in the notes or call us at 253-606-3183 Thank you.