Standard PVC boxes crack under installation stress when the nail drive forces the box against an uneven stud face, or loosen over time when conduit weight pulls on nail tabs in an unconditioned garage or basement with wide seasonal temperature swings. 3/4-inch knockouts accept larger conduit runs for bigger circuits — the trade size that electricians use for 20-amp and 30-amp circuits, water heater runs, and dryer or range circuits. PVC construction handles damp basement and garage environments where steel boxes corrode. Type X rating is required in fire-rated wall assemblies per local code in Nebraska and Iowa. Integral nail tabs hold position through framing and drywall without spinning or working loose. Round profile matches standard round fixture canopies without trimming or modificati Stocked at Crofton Lumber and Akron Lumber.