Graduations are printed in bold, easy-to-read black ink and are accurate to +/-2%. Large white marking area provides excellent contrast for identification. Easy to write on flat surface polyethylene (HDPE) caps feature integrated leak-proof seal. Tubes include graduations molded into the conical bottom, ideal for pellet viewing and small volume quantification. Convenient zip-closure bag is a practical alternative to folding and taping opened bags. Easily refill reusable racks with tubes packed in bags.