Adjustable inner corner, cut-concealing, halogen-free, for SL 20x80mm decor aluminum. Inner corner as a molded part for the electrical installation duct system, skirting board duct according to DIN EN 50085-1 as a device installation duct. Cut-concealing inner corner for snapping onto the lower part. The axially angle-adjustable (83-135 degrees) and simultaneously extendable inner corner enables the compensation of structural inaccuracies and better compliance with bending radii.