Hornady Dust Cover for the Case Trimmer. The Dust Cover is a hand little itme that can prevent dust and grime from fouling your Case Trimmer. The Dust Cover is made from high quality Nylon and is made to last. The Dust Cover is form fitted to ensure it completely covers your Case Trimmer. To keep your Case Trimmer looking and functioning like new, cover it with the Hornady Dust Cover.