Riser for lightshafts with a width of 150 (Building 169) cm. and a depth of 70 cm. Suitable for walking, step adjustable in the ranges of 9-29 cm. (1 riser), 37-58 cm. (2 risers), 65-86 cm. (3 risers).

Note: Requires the use of the reinforcement framework in the case of more than one riser.