Crescent shaped, external and radially mounted Retaining Rings are ideal for low clearance applications. They are geometrical in shape for concentric radial performance. The 2103-5103 family of External, Radial Mount retaining rings are available in shaft diameter sizes between 0.125 and 0.812 inches, and groove sizes between 0.106 and 0.732 inches. Ring thicknesses between 0.015 and 0.042 inches. Excellent retaining ring for tight spaces.