Look you old goat, every shade tree mechanic knows that doohickey, whatchacallit, a gotdamnit, and widget are all very technical. I was close enough to be "exactly right"

Someone else can take my turn for now.

It is a weight that screws into the end of a barbell. One of those little had held girlie barbells that chicks hold when they do aerobics.

IUD ???

How big is it?

Is it some kind of piston head?

You have got to be kidding me! Check out this :

lol