RCBS® Trim Pro Case Trimmers feature uniquely shaped shell holders to firmly hold rifle and pistol cases in perfect alignment with the cutter. This system allows for accurate and repeatable case trimming lengths and leaves the case mouths square to the body. Trim Pro Shell Holders are numbered the same as standard shell holders to simplify identification and use. They’re available individually, or in pre-packs, for most popular rifle and pistol cartridges.