There was discussion before but I lost that thread.
These have 12 leds, use 3W and supposed to be 600 lumens used as G4 lamp replacements.
I bought 10, got $1.29 ea. (checked the receipt) Just looked on site, price went up!
Turns out that G4 is supposed to be 12VAC and these disks have rectifiers. Most G4 bulbs are halogen bulbs, car headlight type for spotlights.
There was some concern that 12VAC peaks > 12V and 12VDC might give poor light. It might do better with another volt or 2 but it throws a bright light on 12DC.
It'd make a good flashlight or bike headlight.
For the price, I bought a few.