I’ve come across this particular item quite many times while I was browsing the web. Only now I found it’s source.
It’s sold in Amazon for $5.98 for a set of five. There’s also a set of ten which is priced at $9.74.
It’s basically tiny hands that can be fitted into the tip of the fingers. There’s no use for this other than pure entertainment.
It’s also a type of finger puppet.