Thin-wall plastic switch boxes crack under the torque of installing and replacing outlets and switches over years of use - especially in basement garages and exterior walls where temperature swings stress the plastic. Once the box cracks, you're opening the wall to replace it. 1/2-inch knockouts accept standard PVC male adapters for residential wiring runs - the most common trade size for 15 and 20-amp circuits. FS (Fset) designation means the box has an integral face seal that prevents air leakage when the device cover plate is installed - relevant for exterior walls and conditioned basements where air sealing matters in Iowa and Nebraska. 1-3/4-inch depth provides wiring space for the device and wire connections inside the box. Pre-attached nail tabs install in one drive - position and n Stocked at Crofton Lumber and Akron Lumber.