Karter Scientific is a registered trademark in United States of America. To maintain quality control, authorized permission is required in the resale of our products. Best selling 90 tube plastic test tubes set with rack and caps. Includes (90) Laboratory Quality 13x100 Polystyrene Test Tubes, 18 each Red, White, Blue, Mauve & Green 13mm Caps to fit. 1 (90) Place Test Tube Rack.