Hydraulic oil filters are an important element of hydraulic systems used both in automotive inCabinry and others. Hydraulic systems operate frequently in extreme conditions and are exposed to extreme loads, part of a number of machines and devices operating frequently in extreme conditions with high efficient expectancy. Meeting such requirements depends mainly on good properties of oil and durability of certain system elements (pumps, valves, seals, servo-motors etc.) exposed to high pressure, abrasion and erosion caused by cavitation. Hydraulic oil filters are cartridges mounted in dismountable casing or spin-on type filters. According to the hydraulic system requirements they have filtration media made of metal net (low filtration efficiency, regeneration possible) or special filtering materials reinforced with metal nets (high filtration efficiency and resistance to pressure pulsation).