This 500mL (16 ounce) Unitary? safety wash bottle has a unique vent system which keeps hazardous volatile liquids in the wash bottle and off the lab bench. Made from low-density polyethylene (LDPE) it has a polytetrafluoroethylene (PTFE) membrane and a vented polypropylene (PP) closure. A strong steady stream of liquid is dispensed when the wash bottle is squeezed. The Unitary? design prevents contamination when filling the bottle; there is no draw tube assembly to pick-up contamination off the lab bench. To prevent cross-contamination the bottle has a natural color bar below the chemical name distilled water which corresponds to the natural colored closure. Material: LDPE bottle with a PTFE membrane and a vented PP closure. Color: natural. Chemical: distilled water. Closure size: 38mm. Capacity: 500mL. Nalgene #: 2436-0505.