The types of pavement drain inlets in common use include curb inlets, gutter inlets and combination inlets. A curb inlet is just an opening in the curb as shown in the image at the left. A combination inlet has both a curb opening and a grate opening in the bottom of the gutter as shown in the image at the right. Gutter inlets typically have a grate over the opening, while curb inlets are typically open without a grate, as shown in the pictures. A sketch of a depressed gutter inlet is shown at the bottom left.