Rather than making return service calls to fine-tune adjustable sills on entry doors, try the Z-Series Articulating Cap Sill (ZAC). The self-adjusting ZAC articulates 1/8 inch under any conditions, compensating for nuances in house settling and door assembly, and ensuring a tight seal against water and air infiltration. The system features a spring-loaded sill cap and a custom door bottom. 800.334.2006. enduraproducts.com