Roller bottles, Corning. Surface area: 850cm². Easy Grip/Vent Cap. Graduations. Roller Bottles are manufactured from virgin polystyrene, the caps from HDPE. Sterilized by gamma radiation and certified non pyrogenic, these bottles are treated for optimal cell attachment. One-piece seamless construction with printed graduations. Printed lot numbers to aid in product traceability. Both resins meet the USP Class Vl requirements for plastic containers and closures.