Our Square Gutter and Fittings are manufactured by UK market leaders FloPlast.Internal Stop Ends are clipped into a fitting such an angle or running outlet to effectively cap off the guttering at that fitting.The stop end clips down and compresses the seal at the bottom of the angle or outlet, thus providing a watertight seal. Fittings with internal stop ends inserted should be supported by fixing to the fascia board to prevent the guttering from collecting water at that point and sagging.If you need any further advice any aspect of your Gutter Installation please take a look at our Guides and Tips Section.