This is an old telephone splice. Each conductor is wrapped in a cloth-like material rather than the newer plastic jacket. Each wire has to be individually striped, twisted together with another one, dipped in molten lead (not solder), and a cloth sleeve slid over it.

Those end caps are lead.

I think it was said that this was a 100 pair cable, and it would take two people working 8 hour days about 2 days to complete this one splice. Yikes!