These classic French hook earwires are made of nickel-free brass with an antique copper finish.  Hole Size: about 2mm open loop Sold per bag of 40 hooks (enough for 20 earring pairs)...

These gunmetal-finished earring hooks are made of nickel-free brass. Hole Size: about 2mm open loop Sold per bag of 40 hooks (enough for 20 earring pairs).  

These gold finished earring hooks are made of nickel-free brass. Hole Size: about 2mm open loop Sold per bag of 40 hooks (enough for 20 earring pairs).  

These earwires are made of brass with an antique copper finish. Hole Size: about 1.5mm Sold per bag of 40 earwires.