Packaging Design Puli Safety Pill Bottle by Qidan Yan Puli is a safety pill bottle with a double-cap closure. The outer cap is connected to the inner cap by tracks. In the initial position, the outer cap turns freely while the inner cap stays still. An adult can pull the outer cap so that protrusions and depressions engage the two caps, which then rotate together to open the bottle. Children find the outer cap hard to pull because the channel is narrow, so the contents stay protected. The flat body recalls a hip flask, hints at the pulling action and is easy to carry. Puli is made of HDPE by injection molding.