As the ogee system is not symmetrical, internal and external corners are different fittings.The product image clarifies the difference but the most common use for an internal 135 degree angle is at the point where a bay window connects to the main fascia line on the roof.
The Cast Iron Ogee Gutter Internal Angle - 135 Degree x 115mm Primed would be best suited for residential roofs requiring an aesthetically pleasing and durable metal roofing solution.
