Features18" diameter2" Vent, 2" Discharge4" Combo inlet hubSewage basins are watertight and gas tight when properly installedDurable polyethylene structural foam coverOne piece, seam free construction on all basinsReady to install for economical and simple installationTemperature rated 130 deg FSpecificationsSize: 18 x 30 in.Vent Split Size: 2 in..