Apparatus and installations for use in water treatment; filters for drinking water; apparatus for water treatment, water filtering apparatus, water conditioning units; filtering and water filtering apparatus using carbon-based technology, notably with activated carbon, carbon blocks and carbon pellets; gravity filters, manually-operated filter cartridges, filter cartridges containing ionic and/or adsorbent exchangers for water filters, kettles, coffee machines, tea machines, espresso coffee machines, samovars; parts and fittings for the aforesaid goods, in particular refillable elements, cartridges and spare parts