I bought TWO Sena Stryker helmets within 6 months of each other.  BOTH went dead after a years' use.  I've had several communications with the company about this.  After providing all the information they requested, they stopped communicating.  I'm assuming it's a battery issue, but changing the batteries in a Stryker is not something I will attempt to do because it involves ripping the helmet apart and messing with circuit boards and soldering.  A helmet this expensive shouldn't be like this.