Acid dyes are dyes capable of ionic bonding with polyamide (nylon) and wool fibers. There are Suncid E, Suncid N, Suncid F, Sunset dyes according to Leveling, Half-Milling, Metal-Complex structure. Suncid NHF-S and Sunset PA dyes are products that improve the dyeability of the three primary colors among Metal-Complex dyes.