This is a Brainlab Cranial Instrument Set designed for use in surgical navigation and neurosurgery. The set includes a custom-fitted, two-tier stainless steel sterilization tray with various specialized instruments and components. Visible part numbers in the set include the 55791 series (e.g., 55791-01 through 55791-07). The tray features integrated silicone organizers for secure storage. Includes the main outer tray and one removable inner layer as shown in the photos.