Does anyone know where I can purchase the black plastic piece that is shown in the attached picture? What is the correct name for the piece? I tried a LBS today but they didn't have any. I'll check another store but is there a place they can be purchased online in case I can't find one here in town? I don't know what model Dia Compe levers these are. They came from an early 80's Fuji Dynamic 12.

Is it just a cable stop? I've not seen exactly that kind, but cheap aluminum ones are everywhere...

Could give loosescrews.com a try. (https://www.loosescrews.com/ )
Hmmm. Or maybe... https://www.oldroads.com/ .

Have no idea, but they're good places to start.

Could also do a QBP search with one of the big online indie stores (harris cyclery as an example.)

But brokenrobot's right, if they're just the cable/cable housing stops, then you can go ask at your LBS--they'd probably just give you a couple for free--or they also come with housing/cable sets, about $7 at the LBS.

Never seen anything like that. What does it do but look stupid?

An absolutely necessary brake lever part as stated above it is as it does "Cable Stop"

I found some of different types but usable at the older LBS in my area.

In fact, if it IS a cable stop and you can't find one locally, I'd be happy to mail you an aluminum one. I've got a bunch in my "screws and bolts" jar... but I'd be very surprised if your LBS won't sell you one cheaper than postage

You're all correct, it is a cable stop. I'm just getting back into bikes after 22 years and I just drew a blank. I was able to get a couple at a LBS.

Thanks for the information. I appreciate it.

Were you able to get the same black plastic ones? I have a pair from my old Fuji Royale that are exactly the same as in your photo. Free as long as you cover shipping.