These earring hooks are made from nickel-free, lead-free metal alloys.
They are hypoallergenic.
The gauge of these earrings is 20 mm (common gauge of earring hooks). 
They are sold as a pair.
AVOID getting any water, lotions, perfumes, or oils on these earrings.  
 
I hand make each individual piece of jewelry so each piece may vary slightly from what is pictured, perhaps in the hook color or the relative size of the butterfly wing.