The water normally used in industrial and domestic water systems contains a certain amount of suspended solid particles of different nature, such as sand, rust, sludge and so on. These particles, of diameter varying from few microns to few millimetres, often cause damage and corrosion to water systems, taps and electric household appliances. It is therefore necessary (to solve the problem) to install a suitable filter before the system or before the equipment to be protected. GEL security filters of DEPURA line differ in the material and the way they are manufactured.