Stratus ERP Series Dual Rocking Piston Compressors are designed specifically for the demanding job of 24 hour operation. They are ideal for pond aeration systems. The oil-less design safely aerates ponds with no electricity in the water. The shore mounted compressor sends air through tubing to a bottom mounted diffuser for a safe, effective way to aerate ponds. Compressors are available in 115v or 230v.