Rectorseal 83945 Aspen Pumps M4R Tank Pump 115 V (20 ft)Rectorseal 83945 The Aspen Pumps M4R Tank Pump is an automatic condensate removal pump for heating and air conditioning systems. The Aspen M4R Tank Pump boasts many exciting features, all of which make it one of the best tank pumps in the field with unsurpassed build quality and performance as a standard. Features Compact Design without compromising reservoir capacity Unique trap and filter minimize biofilm buildup in the main section of the reservoir