Celltreat 15ml centrifuge tube, foam rack, sterile, 300/case features: 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 foam rack is a sturdy alternative to disposable paperboard racks 50 tubes per foam rack, case quantity of 300