Restore functionality to your Bose QuietComfort 45 or 35 I/II headphones with this replacement power button, Bluetooth mode sliding switch, and spring assembly. This genuine part from Bose ensures seamless integration and reliable performance. The power button allows you to conveniently turn your headphones on and off, while the sliding switch enables smooth transitions between Bluetooth and wired modes. The included spring ensures tactile feedback and a satisfying click when operating the controls. With this replacement kit, you can extend the lifespan of your premium audio gear and enjoy uninterrupted listening experiences.