Shatter-proof plastic components. The polystyrene Sedi-Rate pipette is graduated from 0 to 180 millimeters and has a fibrous plug located at the zero mark.. The plug is specifically designed to be a self-sealing aerosol barrier that stops hazardous substances from escaping through the top of the pipette.. The polypropylene Sedi-Rate vial is distinguished by a patented self-sealing stopper that is easily pierced with a transfer pipette or piercing funnel.. The vial is supplied pre-filled with 0.25 mL of 3.8% trisodium citrate diluent..