Sturdy, rigid, polypropylene racks feature interlocking end plates for secure stacking when loaded with tubes up to 10 cm long. Polypropylene is an excellent choice for a test tube rack because it is chemical resistant and will not shatter or stain. Rows are numbered and lettered for easy identification. End plates have handles for easy carrying. Steam autoclavable at 121 ºC. Both racks measure 10-5/8" x 4-7/16" x 5-1/4".