These are monofilament fibres that are available in 2 different deniers (diameter of the fibre) – 15 and 100. The fibre lengths are 5/16” (PVA15), and 1/2” (PVA100). Due to the fine nature of these fibres, and the fact that they disperse into monofilament fibres, they are less likely to be visible in finished surface. How visible they are in relation to each other is in direct proportion to their various diameters (15 is least visible, 100 is most visible).
Learn more about reinforcements here: