5/8″ MPT is designed to accommodate 3/4″, 1″ or 1-1/4″ diameter tubing.
For use with Ultra 400/550/800 Water Pumps and can be threaded directly into the water chamber cover.
3/4″ MPT is designed to accommodate 3/4", 1" or 1-1/4" diameter tubing. For use with Submersible Pond Filters and Ultra 1100/1500/2000 Water Pumps.