Agar Scientific provides a broad range of tin on carbon and gold on carbon SEM resolution test specimens which have been specially developed in their laboratory for SEM and FEGSEM resolution testing and calibration. The ultra high resolution specimens, gold on carbon, are supplied on stubs or alternatively unmounted. They can also be easily mounted on a thin substrate enabling resolution checking to be carried out prior to calibration. The ultra thin substrate, 0.2 mm thick, means this can be achieved with minimal changes to the working distance or focusing conditions. Particle size is in the range of < 2nm up to 30nm.and is suitable for testing at instrument magnifications of x50,000 and above. The company supplies one of the broadest ranges of accessories and consumables for microscopy. The complete range is available in either electronic or printed-catalogue form.