About this item Double W-shaped Tube Core to Enhance Stability. SpinFit patented spinnable 3D axis that bends to fit unique ear canals' angle like customized. Medical-Grade silicone reduces allergic reactions. A popular choice among audiophiles. Most affordable upgrade of the sound and wearing experience to IEMs. Fits nozzle diameter of 5 - 6 mm. Dimensions: 3.07 x 2.95 x 0.87 inches.