The Möller-Wedel Optical SIAM is a measuring device for determining the angle between the primary and secondary image on windscreens in accordance with ECE regulation ECE R43. The device consists of an eye-safe laser beam source (laser safety class 2), a telescope and the evaluation software. Due to the optical arrangement the measurement is independent of the distance between light source, windshield and telescope. The included software allows the automatic determination of the angle as well as the recording of the angle together with the measuring position on the windshield in a protocol.