Corning tubes are available with either plug seal or flat top caps. Fifteen- and 50-mL tubes feature black printed graduations and a white writing patch; 250- and 500-mL tubes feature molded-in graduations. All are sterile and certified nonpyrogenic. The 50-mL tube 17400-44 is self-standing. You can color code the 15- and 50-mL plug seal tubes using the cap inserts sold separately on page 163. The 250- and 500-mL tubes require adapters 17404-00 and 17404-05 respectively, sold separately. Warning: This product is not approved or intended for, and should not be used for medical, clinical, surgical or other patient oriented applications.