$ 436.87
Details
The Walton and Beckett graticule is used for counting fibrous dust (asbestos or glass fibers) and particularly useful where the majority of fibers to be counted are shorter than 5 microns. The circle is divided into four by two diametrical lines scaled in units of 5 and 3 microns respectively. 3 and 5 microns are the critical measurements of fiber lengths and diameters used in fiber counting. Walton and Beckett have a series of shapes for comparison with fibers, and include shapes with an aspect ratio of 3:1 or 5:1 essential for such analysis. IMPORTANT NOTE: The circle on these Walton & Beckett graticules must represent 100 microns at the stage and each one must be manufactured to suit the individual instrument. Details should be provided with your order-calibration factor, objective and eypiece magnification, diameter of graticuple disc required, and microscope make/model. 5:1 ratio is useful where the majority of fibers to be counted are shorter than 5 um, glass sandwich
