Hotwheels track joiner
thingiverse
Proved impossible to find anywhere else. So I took the dimensions of the ones we had and made a replica. Used in some hotwheels sets to join the track peices. Once lost, irreplacable, until now. Not sure which sets this works with best and I don't know the name of the set my son has. But if the part you're missing looks like this, then it probably is.
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