Interlocking on all sides! 

Our user friendly cube rack is a must for any laboratory. It accommodates (4) 50mL tubes, (10) 15mL conical tubes, (12) 12 x 75 or 12 x 100 tubes, or (16) 1.5 to 2.0mL microcentrifuge tubes. Polypropylene racks slide together, allowing you to work with different tubes on as many connected racks as desired. Autoclavable. Available in natural, green, pink, yellow, or assorted colors (one each of blue, green, yellow, orange, and pink). Rack measures 4 1/4 x 4 1/4 x 4 1/2". Packs of 5