He faucet aerator is made of ABS plastic, the gasket is made of silicone, and the fine mesh has good filtering effect, it is long-lasting for you to use. Each pack contains 20 pieces of faucet aerators and 40 pieces of rubber washers(M22 & M24) in a pack, sufficient for your different needs. The outer diameter of the top is 21mm/0.83inch, that of the bottom is 19mm/0.74inch, standard size for built-in insert mounting and fit most standard M22, M24 faucet. Please check your aerator size before purchase! The strainer inside can filter out most impurities, very convenient for you to use. Suitable for the installation and replacement of faucet fittings at homes, hotels, public facilities and other places, which is conducive to water saving and filtering water.