Alpen High Performance Products announced the availability of its new Zenith Sliding Glass Door series. Alpen's Zenith series was developed in an effort to provide customers with a bigger door option that is easier to open and close, while also providing increased energy efficiency and the strength to meet regulations that are being implemented nationwide related to wind and climate change. The series includes two distinct models: the Grandline and the Narrowline, each offering unique features and performance benefits.