Faucet Aerator Thread Gauge Identify thread pitch & diameter for 20 of the most common aerator sizes from 1/4-18 to 15/16-27 Manufactured from aluminum with the thread sizes in contrasting black print. Includes (8) female threaded holes to measure male aerator thread sizes. Includes (12) male threaded studs to measure female aerator thread sizes. Carry in your tool box or use the pre-drilled holes for peg board mounting.