Cartridges and valves: the soul of single lever mixers and classic taps cartridges for mixers and valves for classic taps are fundamental components that play a crucial role in ensuring correct functioning of the taps. Ceramic disc cartridges for mixers allow precise control of the mixing of hot and cold water. The valves are accessories found inside traditional taps. Valves are often made of durable material, such as brass and ceramic, to ensure long life and prevent water leaks.