Used to seal the point at which two upward slopes meet, which can be both along the ridge of the roof as well as covering for the hip.  Either woodgrip or self-drill lap TEK screws are applied through the ribs of the metal.  Since debris, insects, and blowing rain can find easy access under the ridge cap, closures are required to either completely or partially seal the opening.  Closures under ridge caps come in two types: solid and vented.