Our supplier of suction filters is MP Filtri S.p.A. MP Filtri suction filters are available in 3 styles: STR series immersed filters FAS external filters, for mounting above the oil level SF2 external filters, for mounting semi-immersed under the oil level SF2 semi-immersed filters, which shut off oil flow while the filter element is being replaced, replace the butterfly valves usually used for servicing hydraulic pumps.   MP Filtri STR Data sheet: STR, MPA – MPM Submerged suction filter, flow rates up to 900 l/min (238 gpm), threaded connections from 3/8” to 3” BSP/NPT.   MP Filtri FAS Data sheet: FAS Semi-submerged positive head suction filter, flow rates up to 160 l/min (43 gpm), threaded connections up to 1 1/2” BSP/NPT/SAE and 1 1/2″ SAE 3000 PSI flanged connections.   MP Filtri SF2 250 Data sheet: SF2250 Semi-submerged positive head suction filter, flow rates up to 850 l/min (225 gpm), flanged connections up to 4″ SAE 3000 PSI.   MP Filtri SF2 500 Data sheet: SF2500 External suction filter, flow rates up to 850 l/min (225 gpm), threaded connections up to 1/2” to 2 1/2” BSP/NPT and flanged connections up to 3 1/2” SAE 3000 PSI....