How do you seal the end of heat shrink so neatly or can you buy heat shrink with a closed end?
I think it's a heat shrink tube that's closed on the end. Look at how straight the material is at the top towards the ratchet head end. I don't think a dip would have that straight of a line.

Video showing it from a factory tour:

Video showing it from a factory tour:

How do you seal the end of heat shrink so neatly or can you buy heat shrink with a closed end?
You can absolutely dip straight -- ever see a pair of channellocks?![]()
Go check your Channellocks. You'll see a drip forming on the end of each handle. That's the work of gravity. It's that way on all dipped plier handles.