Hear music the way it was meant to be heard. A simple audio hack that gives you the isolation you want with the comfort you need. Seals ear canal from environmental distractions. Enjoy music without raising the volume to compensate for external noise. Precise, optimal seal channels sound directly into the ear canal to transform your listening experience. Heat activated memory foam expands to unique ear canal shape, creating a custom, secure fit for amazing in-ear retention. Acoustically transparent filter (Only for Tx models) to prevent wax and debris from entering the sound port. Keeps your earphone sound quality how you like it. Specs Colors: Black Height: Small / Medium / Large: 10.67 mm ± 0.65 mm (0.420" ± 0.025") Diameter at proximal end (end attaching to device): Medium: 12.45 mm ± 0.50 mm (0.490" ± 0.020") Materials: Polyurethane foam, thermoplastic elastomer (all RoHS compliant).