TriGlow LED Linkable Shop Lights, 4-Pack

What is the lumens?

Did you happen to read the Features tab? It’s clearly shows what the lumens are.
“This fixture features a cool white glow (4100K) and high luminous efficiency with 4100 lumen output”

Do they in fact have a pull chain on/off switch? Pictures looks like it!

Mine do. Got this set last time they were offered. They are very worth the price imo. No complaints at all.

Similar models that likely came from the same Chinese factory sell for the same or a few bucks less on Amazon.

I don’t see anything that makes this brand anything special. Nothing special here

$15/ea (iirc, less than $20 anyway) at your local ReStore (MA/NH) when I bought mine a few months ago.

Are the “bulbs” replaceable, or when the LEDs hit their’ EOL, do I have to buy a whole new unit?

They are not replaceable. They have an average 50K hour life though.