TREE PLANTING TIMBERLINE SAFETY WEAR GLOSSARY# L M Q R X Y Z 2 DENSITY PU SOLE • A lightweight material that is injected in two different densities onto the leather upper. The high density is injected first to create a tough outer skin. The second density is injected at a low density to provide a lightweight inner core for cushion and shock absorption. This material is extremely abrasion resistant, slip resistant and flexible.