The Cokin Z-PRO 142 Net #1 White Resin Filter is available in white and black, grades 1 and 2, with #2 having the greater effect. The black net filter softens fine details with no change in contrast, while the white net filters not only soften details BUT also lower contrast.
Z-PRO Filters are made of CR39 Resin which is a reputable lightweight and shock-resistant optical material also used for ophthalmic glasses. The Z-PRO Series is recommended for focal lengths of 20mm onwards (in the 35mm format).
Cokin Net Filter Chart
Cokin Black Net 1 is #143
Cokin Black Net 2 is #145
Cokin White Net 1 is #142
Cokin White Net 2 is #144