Cassette tapes come in several types:

• Type I, normal bias tape made with ferric oxide, brown colour
• Type II, high-bias tape made with chromium dioxide and/or cobalt particles, with blue or black colour. This tape is no longer manufactured but we still have some new tape in stock.
• Type IV, metal tape needing even higher recording bias, black colour, with extremely loud output levels but also higher tape hiss. There is practically no more new Type IV tape left in the world.