In Etymotic design, the Dual Flange Ear tip is an evolution. Etymotic ear tips allow 3 possible points of contact in the ear canal that seal the ear better than the single dome silicone tips on many products using a 3-flange system. A tip that is lighter, more secure, and seals just as well as their conventional 3-flange tip. This kit includes three pairs of Small/ Medium/ Large-size ear tips designed to match Etymotic earphones. The big tip has the widest external diameter of 11 mm. These tips would also fit other brands of earphones with an inside diameter of approximately 3 mm.