Please note this internal corner piece is compatible with the 10mm, 18mm and 25mm uPVC square edged fascia boards. Dimensions Width: 300mm. Material: uPVC. Guarantee: 20 years. Angle: 135 internal. Description The plain fascia system is a clean, modern style which includes the 10mm thick fascia board and a full range of accessories to ensure a neat and professional installation. The plain fascia system comes in a wide range of solid colours, woodgrain finishes and fascia widths.