3M™ RelyX™ fiber post drill size 3, 56866. Features: - Helping you deliver long-lasting, esthetic restorations, the 3M™ RelyX™ fiber post drill is designed for use with 3M™ RelyX™ fiber posts. - Fiber post drills are color-coded to match the posts for convenience. Package contents: - 1 Drill – Size 3 (1.9 mm dia.) Blue.