The OSL laser beam expanders from Optical Surfaces (Surrey, UK) are designed to provide achromatic expansion of a collimated input source. With aluminum coatings they can operate from the UV to far IR range without adjustment. Alignment aids are supplied with each beam expander to ensure correct beam pointing. Specialist beam expanders requiring larger apertures (up to 400mm) or higher magnification (up to 100x) are available, as are both horizontal and vertical beam displacements. Custom beam expanders with a focusing capability for a given far field can be supplied for performance in LIDAR applications. An alternative beam expander is also available using two off-axis parabola with a common focus for Fizeau applications. OSL beam expanders are housed in a box assembly allowing them to be fixed to an optical table and transported to different sites without internal realignment. Test interferograms and an OPD map are supplied with every beam expander.