SHOP-VAC Wet/Dry Vacuum Replacement Drain Cap for 2-3/4" Tank Drains - 7446800 Cap outside diameter: 2-7/8" (2.875") Replacement drain cover for Shop-Vac brand wet / dry vacuums with a tank drain measuring 2-3/4 inch across Manufacturer Part No.: 744-68-00 Genuine Shop-Vac Replacement Part