Fuel Resistant Waterproof Rubber Seal Strip For Sealing Larger Pipe Unions Ultra Precision Cord Extrusions: Our o-ring cords are available with extruded tolerances of +/- .0025” or better. For critical applications that demand close tolerances we have the technology to meet your needs. There is no need for post extrusion grinding! These extrusions are converted into bonded o-rings, door seals, encapsulated o-rings and various sealing devices. Our finished cord extrusions are