These PET plastic vials feature the clarity of glass and waste disposal advantages of plastic. Practically unbreakable, these vials have minimal background counts and low permeability to solvents. Polyethylene terephthalate (PET) construction. Vials have capacity of 20 ml. Polypropylene screw cap. Size of cap, 22 mm. With cap, dimensions are 27 x 61 mm.