Arizona Simi-Seal Dubbing is a very popular dubbing that has just the right amount of flash. We love Arizona Simi-Seal for leech patterns and for steelhead/salmon flies. It is also excellent on larger nymphs when you want a longer, coarse fiber and some flash.
Arizona Simi-Seal is a coarse mix of natural and synthetic materials that are blended together for extra flash and body. It is also a good "more flashy" seal substitute.