The Denver is a 6" tall block that has a rear lip system that provides a 3/4" backset that eases installation and makes the face of wall uniform when installing them. It is a gravity retaining wall which means it needs no pins or clips to install it. This saves time and money without having to buy extra parts or install other items into the wall. The hollow core design saves weight in shipping and eases installation over competing block. This also helps with drainage and connection between the units when the cells are properly filled with crushed rock or pea gravel. This block is designed for residential, commercial and industrial type applications and can be engineered to be higher than 3.5' tall. These are available in 3 colors - gray, tan, and red/ black and 2 different styles - beveled and straight face.