Part identification needed

I am in the process of repairing/rebuilding the wiring harnesses on my ’64 Barracuda. Need help identifying this part. It is part of the body wiring harness (wiring in the trunk) and is located just forward of the jack. It appears to be molded over the wires and is part of the wiring loom. What is it? What does it do? Is it necessary? Is a replacement available? Any help will be greatly appreciated.

Thanks, Ken