Faucet Aerators - Hidden
Hidden, or "cache" aerators require a tool to remove them.
These aerators are used for both an improved aesthetic as well as for being tamper resistant.
Using this set of tools to remove hidden aerators is helpful as the color of the tool indicates the diameter of the aerator thread, with a few exceptions, of course.
If your faucet aerator has a blue o-ring, like the one shown here, then the color of the tool you used is guaranteed to indicate the diameter.
Key Color = Diameter
Yellow = 16.5mm
Green = 18.5mm
Red = 21.5mm
Grey = 24mm
Hidden Aerator Keys - A different use...
Which thread sizes fit inside which keys?
We can use these keys in a different way: by comparing faucet aerator threads to the inside measurement of these keys!
9/16"
Fits in the yellow key
5/8"
Fits in the green key but not the yellow key
11/16"
Fits in the red key but not the green key
3/4"
Fits in the grey key but not the red key
13/16"
Almost fits in the grey key
15/16"
Too large to fit in any key
16 and 16.5mm
Fits in the green key but not the yellow key
18 and 18.5mm
Fits in the red key, barely, but not the green key
20mm and larger
Too large to fit in any key