90 Degree Gutter Angles are used to turn the gutter around the corner of a building. As the system is symmetrical, both internal and external corners use the same fitting - there is no difference.You should always support a gutter angle by positioning a fascia bracket within 150mm on both sides of the angle. This will prevent the fitting from sagging when it is weighed down by water or snow.Our PBSL Group video of this product can be viewed here;