This is a Pentair Plastic Multiport Valve Clamp with Screw and Nut for Six-Way 1-1/2 Inch HiFlow Valve, Sand Dollar Filter Systems, Meteor Filter Systems.
Used on filters manufactured after 6-2004 including: Sand Dollar Top Mount Filters, MultiPort Top Mount/Side Mount Valves, Cristal-Flo II High-Rate Sand Filters, and Tagelus TA 30D Filters.