Globe Scientific TUFFBLOK 4-Way PP tube racks for 50/15/1.5/0.5 mL tubes. Standard link-together (456940AST/B/C/P/G/N/Y) and TUFFBLOK XL wider wells (456945AST/B/C/P/G/N/Y). 7 colors each, autoclavable. 5/pack, CS/20.