These Nalgene 2202 large, low density polyethylene bottles ship with polypropylene caps. For storing chemicals and standards, collecting and storing distilled water. LDPE Bottles are translucent and offer flexibility, impact resistance and visibility of contents. The extremely low trace metal content in low density polyethylene makes them ideal for trace metal analysis. These bottles provide excellent chemical resistance to most acids, bases and alcohols. The 4- and 8-liter sizes (Cat. Nos. B6760-2 and B6760-3) have a built-in shoulder loop for attaching an identification tag.