Standard Internal Retaining Rings | Arcon Ring- large snap ring pliers oreillys chart pdf ,Arcon Ring manufactures the industry's most reliable carbon spring steel internal retaining rings to sizes ranging from .250" to 1.000" to meet your needs. They can also be custom-designed to your specifications. Visit our site to browse our internal retaining ringssnap fasteners - Sizes15/11/2010· snap fasteners. In most of the world, snap fasteners are sized by their diameter in millimeters, in increments of whole millimeters. Fasteners from 6 mm to 19 mm are commonly available, and 30 mm are made. In the United States, snap fasteners are sized in several ways. One is simply the diameter in fractions of an inch.