These are weird little adapters that have a 4mm socket to take a Banana Plug and convert it into an Alligator clip of sorts.
A press button to open the jaws.
Note that only one side of the jaws is metal the other side plastic, my guess is so that the “off side” doesn’t risk making contacts where you don’t want it to, marring the back side of PCB or something (or maybe it’s just cheaper to make!).
Anyway, these are just little oddities I thought might come in handy if you have some banana plug leads and you need alligator clip leads instead.
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