This is a set of 8 keys sizes # 5-12 in solid brass. 3.4 mm,3.6 mm,3.8 mm, 4.0 mm,4.2 mm,4.4 mm,4.6 mm and 4.8 mm.
You will gets some tarnishing with brass but they will never rust.
This set is for the collector or repairman that needs to know what size of key that you need.
These are made in USA