Rectangular aerators, which are an industry standard for flow-aid aeration style in concrete batch plants for cement and flyash silos, are available in the industry standard size of 3.75-inch x 7.5-inch. The units can be mounted from outside the bin using the available external mounting kit. All aerators are plated steel with either cotton or fiberglass diffusers. Aerators can be mounted to cover an effective area of 10-inch radius from the aerator center. The rugged, reliable devices are low in cost and immediately available from stock with competitive pricing and OEM or re-sale discounts available.