The RCBS Case Trimmer Collet #1 operates like a draw collet on a lathe to securely hold brass cases during precision trimming operations for consistent case length preparation.RCBS Case Trimmer Collet #1Draw collet design for secure case holdingPrecision trimming to exact case length specificationsCompatible with RCBS Rotary Case Trimmer and Rotary Case Trimmer-2 onlyEssential accessory for brass case preparationPerfect for reloaders who demand precise case length consistency and professional-quality brass preparation for accurate ammunition assembly.