As steel gutters are not symmetrical, gutter angles are either internal or external.andnbsp;The product image clarifies the difference but essentially if you are stood in front of an external corner, the corner goes away from you out of sight. External corners are usually used on all 90 changes of direction except at the foot of a valley, where you would use an internal corner. An internal angle is one that comes towards you as you stand in front of it.Galeco 90 Degree steel gutter angles should be fitted with unions to make connections.Angles should be supported by installing a fascia bracket within 150mm of the corner.