1.Material:PS(Polystyrene) 2.Brand:WHB 3.Sterilized by gamma irradiation 4.Dnase/Rnase and pyrogen free 5.Available with 3 different growth areas of 50ml(25cm2),250ml(75cm2),600ml(175cm2) 6.Flasks surface is flat and free from striation to maximize usable growth area 7.2 different cap styles (Seal and Breathable) can be used in both open and closed systems. 8.breathable cap have 0.2um hydrophobic menbrane,conducive to exchange gas,prevent microorganisms. 9.Innovative angled neck design offers good pipet and cell scraper access in 10.Upper triangular and wider base shape provides stability 11.Protrudent ridge on the back side of the flask makes it easy for stacking 12.Special area near the neck for easy mark writing 13.Both flask sides have engraved graduationStrict integrity tested