Rockford rp-25-ss - 3" grease interceptor - 50 lbs capacity - 25 gpm - stainless steel a rockford separator is designed for exceptionally high efficiency in retaining a wide variety of insoluble wastes. Maximum water travel with minimized turbulence through the filtering action of its screens prevents evacuation into drainage systems which may cause blocking, stoppages and backups. The rp-ss series is a new line of stainless steel grease interceptors that are inherently stronger and more durable polyethylene. The pdi- and iapmo-approved series includes models for flow rates from 4 gpm to 100 gpm.