Today on the bench: this sweep and marker (swemar) generator for tuning FM band receiver front ends and their common 10.7 MHz IF sections.

It's a modular thing. There are larger frames and other plug-in modules. I've came across pictures of modules for TV alignment on the net.

The serial numbers are interesting

Quick look inside the front end sweeper module. Quite a lot of discrete logic to decode the frequency dials.

Flip side has some botches

Was curious what's in the shielded box.
Couldn't find any service data or schematics. But this doesn't look all that complicated at first glance.