Greiner Bio-One skirted polypropylene tubes have excellent optical clarity and strength. Tubes have blue HDPE caps, graduations, and a marking area. Will withstand 3200 RCF x g in a non-supported rotor, 9500 RCF x g in a supported rotor. Each tube measures 30 mm x 115 mm. RNase free, DNase free, human DNA free, and non-pyrogenic. Sterile.