STARCHECK is a precise and reliable tool for fast measurements in radiation therapy beams. Typical applications are quality control and LINAC beam adjustment measurements with the detector panel embedded in a solid state phantom. The ionization chambers feature an excellent relative response stability, avoiding the need of frequent recalibration. A full set of four profiles is measured every 200 ms, making the device useful for real-time measurements. The excellent spatial resolution of only 3 mm ensures precise measurements even in penumbra regions. The scanning lengths covered by the detectors are 25.2 cm along the principal axes and 34.5 cm along the diagonals. The optional FIELDCHECK phantom allows to measure light field and radiation field. The optional BQ-CHECK phantom is used for contancy check of the beam quality.