Due to extremely high pressure and uncertain fuel quality, the factory injectors in your 2006 or early 2007 Duramax can fail over time. Especially if you're experiencing some white smoke and/or a hard start, you're probably due for at least one injector. If you're in need of replacing one, two, or all eight of your injectors, these are a genuine Bosch, brand new (not remanufactured) replacement injector. And because these truly are brand new, there is no core charge and no need to send in your original injector(s).