15mL Metal Free centrifuge tubes with flat caps in bags. Non Pyrogenic. Lot certified RNase/DNase free. Low Metal Certified to 1ppb of Calcium, Magnesium, Zinc, Iron, Manganese, Copper, Aluminum, Silicon, Nickel, Vanadium, Sodium, Phosphorus, Cobalt, Chromium, Potassium, Lithium, Lead, Selenium, Cadmium, Mercury, and Arsenic. 50 per bag. 10 bags per case. Sterile.