Iwaki America makes external aquarium pumps ranging in flow rates from 420 gallons per hour up to 2000 gallons per hour. Iwaki is unique in that it makes two different models - the MD and the WMD. The Iwaki MD models feature a Japanese motor that is made from cast aluminum, a custom pump designed specifically for aquatic applications and a cooler running pump that runs quieter than the WMD models. They have less parts and are the result of years of research and development. The Iwaki WMD models feature an American motor that are HVAC in design, pumps are made from rolled steel with stamped end plates and tend to be a bit bigger than the MD models. The Iwaki WMD models have the same head pressures and head rates as the Japanese MD models. Each model is a high quality non-metallic centrifugal pump or mag-drive from a leader in the pump industry with the American motor pumps or WMD models are at a lower price point.