Topp B2400SV-2 18" x 30" 2" Side Vent Poly Basin (Undrilled, No Grommet)The Side Vent Sump and Sewage Ejector Basins' unique design has been developed for efficient maintenance, reducing service time dramatically. With the vent pipe remaining intact, gone are the days of cutting then repairing the vent pipe for achieving regular pump maintenance. This approach to the design of this basin easily reduces the time for your service calls by one third. (30 U. S. Gallon Capacity)