Norweco uses a shaft style aerator that injects air into the aerobic tank. It achieves this by spinning a hollow shaft that draws air from the top of the motor down the shaft and then out of the aspirator. This creates the oxygen-rich environment that the aerobic bacteria need to treat the wastewater properly. WSS offers shaft aerators with a 12'' and 14'' leg span. That allows the motor to rest on the access port, while the shaft agitates the wastewater. Our replacement aerators will replace any Norweco Singulair aerator you have.