http://www.sun-trine.com/centrifuge-tube/ Centrifuge Tube Free Sample Plastic Medical Sterile Conical Bottom Centrifuge Tube 15ml for Laboratory Use. Features: 鈼?High quality PP material in accordance with FDA, ultra-transparent wall, easy to observe. 鈼?Graduations are printed in bold, easy-to-read black ink and are accurate to +/-2% 鈼?Non-pyrogenic, DNA-/RNA-free, sterile. 鈼?Large white marking area provides excellent contrast for identification 鈼?Easy to write on flat surface polyethylene (HDPE) caps feature integrated leak-proof seal 鈼?Tubes include graduations molded into the conical bottom, ideal for pellet viewing and small vo