The "ULTIMATE WEAR RING" is the finest wear ring available today. The UWR design alleviates the need for an insulator.  The UWR is made up of a rare poly material that results in a reduction of both the friction and cohesion levels over metal wear rings.  The reduced friction increases hole shot by reducing the horsepower requirment.  The standard size is made to fit a new impeller with a wear ring surface diameter of 7.225". The .010" undersize fits an impeller with a wear ring surface diameter of 7.215" and so on down the line of the sizes available. USPatent# 5324560
Fits Berkeley, Dominator (after serial #1444), American Turbine, Legend, & Aggressor Jet Drives.