ADA Compliant Inswing Exterior Door Threshold - Mill Finish1/2" x 5 5/8" x 36"ADA compliance guidelines specify that a compliant door threshold can be no more than ½" tall. This sill meets the requirements for ADA compliance.Testing has proven that a dam provides a sill with a positive barrier to wind driven air and water infiltration, and is conducive to proper contact between the door bottom and sill, which is crucial to the insulation and maintenance of a structure.