Aerators are designed to cut down on unnecessary water consumption (washing hands, brushing teeth, shaving etc.) from your taps. An aerator serves the following purposes: Prevent splashing Shaping the water stream coming out of the faucet spout Saving water and reducing energy costs Reducing faucet noise Faucet aerators are often used in homes with low water pressure in order to increase the perceived water pressure. Aerator key is used to assist in the safe removal of standard continental size aerators from tap mixer outlets and prevents from scratches while installing. Specifications: 3 x m24mm male tap aerator + 1 x m22mm female tap aerator + 1 x opening/closing key; All high quality made in eu Material: stainless chromed brass Reducing water usage up to 50%