Vibrant coloring keeps your protection highly visible, enabling easy compliance sighting. Self-adjusting polyurethane foam expands upon insertion, ensuring a tight yet comfortable ear-canal seal. Smooth, soil-resistant closed-cell foam skin prevents dirt buildup. Contoured shape fits to a T. Leight Source 500 Refill. Corded/Cordless Pair: Cordless; Shape: T; Material(s): Polyurethane Foam; Noise Reduction Rate (NRR): 32 dB.