Teton Professional UV Clarifiers offer multi-directional 2″ outlet for ease of plumbing, aluminum housing for the 16W model and stainless steel housing on the 40W, 80W, and 120W models. These metal housings have a more reflective capacity for the UVC and are more durable than plastic. Plus, Teton offers a 2-year warranty on the ballast, and a 5-year warranty on the housing.