Stratified epithelium is classified by the cell type on the uppermost layer. Notice that is true for the pictures shown below. They are typically found in locations where constant abrasion is likely, such as mouth, esophagus and vagina. The epithelium at these locations do not have thick layers of Kertain on top, and thus are classified as non-Keratinized. In other words, these are moisturized lining.
Because the uppermost layer of cells are regularly sloughed off by abrasions, they are constantly replenished by an actively dividing basal layer. The basal layers tend to be more cuboidal in shape and the cells being pushed outward gradually take on the flattened morphology.