My Dad wants to resurrect his old M track and locomotives, but the old blue transformer has seen better days so we got a 2nd hand 66470. The manual in the Marklin website seems to show something that you push over the terminals on the back to hold the cable. This 2nd hand one is missing those.

What are they called? And any suggestions on where to get them?

I did some searching but was only finding things that didn't look compatible.
If all else fails then I'll make the connections safe with a few layers of heatshrink tubing, but would much prefer the proper connectors.

This is the link to the manual : 66470 manual at Marklin.de

Regards