This is not your garden variety 3M 33. It is rubber amalgamating tape
used on high voltage splices up to 67kv.
What else is it good for?
I managed to come into 5 cases in an auction thinking I was getting 5
rolls and I have a lifetime supply ... for half of the IBEW.
Anybody want some? Send me a prepaid shipping label and all you want
is free. 20 rolls is a nice fit in a medium priority flat rate box.
I trolled out some on Ebay and Craigslist but no bites so far.

https://i.ebayimg.com/images/g/RBsAA...MO/s-l1600.jpg