AS-568B Standard O-Rings Apple Rubber offers the seal industry's largest inventory of O-rings including every standard AS-568B size, including I.D.'s from 1/32" (.794mm) to 26" (66.04cm), O.D.'s from 3/32" (2.38mm) to 26-1/2" (67.31cm) and cross sections (widths) from 1/32" (.794mm) to 1/4" (6.35mm). We also carry a wide variety of metrics and non-standard sizes. Most likely the size and compound you require is in our stock of over 300,000,000 O-rings. Our O-ring inventory is constantly restocked to assure immediate delivery of any size in large or small quantities.