Aerator key material: the faucet aerator keys are constructed from durable plastic, designed to effectively remove faucet aerators. Quantity and Size: faucet aerators sizes: 16.3 mm, 18.2 mm, 21.3 mm, 23.7 mm, with 3 pieces for each size, totaling 12 pieces, along with 5 faucet aerator removal tools, a sufficient quantity to meet your needs. Suitable for Partial Faucets: please measure the diameter of the internal thread of your faucet before ordering, and verify which size of faucet aerators is compatible; Note: only suitable for female faucets. Easy to use: with these aerator keys, you can effortlessly unscrew your faucet aerator for replacement or cleaning, resolving issues with low flow faucets. Aerator key: assists in removing most faucet aerators; please measure carefully before purchasing to ensure compatibility.