Our bi-directional, vertical slot surface registers are precision engineered for maximum strength and durability, while providing optimum flow volume. They are assembled to tight tolerances using our proprietary TightJoint™ design, which is machined after joining, leaving no glue traces to cause areas of uneven staining or finishing. Surface mount registers are also called "drop-in" vents, because they drop into the duct hole in the floor. Simply remove the old vent and drop in the new vent.