Extremely elastic allows for effortless stretch at head turns and movementsSoft and skin-friendly material prevents discomfortExceptional at transmitting sound from earpiece's speakerTough and long lasting, reliable for daily tasksFor our acoustic tubes, we highly recommend that the acoustic tube be replaced every monthly for heavy usage and 2 months under moderate use. Reason is because the human's body oil, earwax and sweat will latch onto the tube through usage which result in poor hygiene and discomfort. This period of replacement is only recommended and may varies amongst customers.