DORADOselect 3 has been installed more than 6000 times worldwide, and sets the standard for isocenter and reference point marking. DORADOselect 3 consists of two rails at the sides and one rail with a fixed tansversal line and a movable sagittal line at the ceiling. The rails at the sides contain one fixed laser for the transversal line and one movable laser for the lateral line. They may be mounted on the wall or as posts. Alternatively, the whole system may be put up as a bridge.