The Otto 1 ml Cartridge for 13 mm Test Tube Collection Start-Up Kit contains the components necessary to use 1 ml cartridges and 13 mm test tubes with the Otto Specialist. These components are 1 ml Top Rack, 13 mm Test Tube Collection Rack (100 mm test tubes), a 13 mm Tube Spacer for 75 mm test tubes and waste collection. This rack will hold 24 cartridges. No additional component is required for 1 ml cartridges.