The KOSS Sparkplug VCw Noise Isolating Earbuds feature a dynamic element that is positioned just outside the ear and connected to a tubular port structure that is inserted on a soft expandable cushion into the ear canal. The soft foam cushion expands for a custom fit to improve isolation and enhance deep bass and treble clarity. Now with improved slow memory ear cushion made of hydrophillic, formed urethane, you are guaranteed a custom fit every time.