LAING E10-NSTN1W-19 Spa Circulation Pump High density ceramic bearing ball and graphite impeller bearing cap designed for high efficiency and long life. Highly efficient and ultra quiet spherical motor design. Pump is designed for continuous operation. All ratings are within working limits of the motor Unique patented design has no mechanical seal which is a potential leak path. Embedded microprocessor control is self-regulating and available with variable speed dial control (potentiometer) on the pump or as an optional PWM input for OEM. Built in DRY RUN protection is programmed into the software to help eliminate motor and pump damage if the pump is ran w