Möller-Wedel Optical GmbH offers attachment achromats with different focal lengths for autocollimators/testing telescopes/collimators as well as for the measuring combination MELOS 530 and the centering testing instrument CIFOS. For interferometers, different types of Fizeau objectives and plane plates are offered. Test wedges are excellent for quickly checking the accuracy of autocollimators and collimator/telescope combinations such as the SIAM.